A character is very good at his profession, but is completely unable or unwilling to use this ability to help himself or his own family. This is seen most often with therapists.
It may be justified in the case of therapists, because to analyze more effectively, a therapist has to be outside the problem. Think of it like a maze. Is it easier to see the path to the exit in the middle of the maze, or looking down from above? In fact, professional counseling and psychology organizations classify counseling those the therapist has an emotional attachment to as a "dual relationship." They are ethically questionable and always to be avoided in professional work.
Apparently, if Mental is to be believed, psychologists have a lot of trouble in relationships specifically because they overanalyze every facet of their partners' (and/or childrens') lives, and their partners don't appreciate psychological tricks used in arguments ("Oh, you're not really mad at me. You're self-projecting feelings of inadequacy toward your mother through means of passive-aggre..." *slap*).
The same justification can be used for doctors (their emotional attachment can blind them to what's wrong with themselves or those they love, or make them unable to use a risky treatment), so many hospitals have policies that forbid doctors to practice on family members (the exception is when they're the only specialist available, e.g. a venom specialist whose family member just got bitten by a snake). For lawyers, it's not verboten, as it is a legal option, but custom and best practices advise against both self-representation (as in the expression, "A man who represents himself in court has A Fool for a Client") and representing family (by the same principle).note Note that it is very strongly discouraged for lawyers to represent those with whom they have had a sexual relationship, and outright forbidden if the sexual relationship began after the attorney-client one.
If you happen to be wondering why emotional attachment would stop the cobbler repairing his children's shoes, that's not the reason. He's just too busy doing paid work.
Another name for this is "vocational irony", which is a form of situational irony. This is the supertrope of one type of Preacher's Kid, a.k.a. "The Minister's Children Have No Morals".
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Doctor Bombei, the greatest Choujin physician in the Kinnikuman universe, succumbed to a malignant tumor because he spent so much time watching other Choujins' health he didn't pay attention to his own.
The history of Mr. Riddles in Zatch Bell!, in the original Japanese, involves him as a surgeon trying to save his grandson, but failing, sending him into a depression that is only lifted once Kido arrives.
In One Piece Monkey D. Garp is a legendary marine. While there is no doubt he tried to turn his descendants to that path, ultimately his son became a revolutionary and the world's most wanted criminal, and his grandsons became powerful pirates, one a commander for the Whitebeard Pirates and the other a rookie with enormous potential and one of the likely candidates to become the Pirate King.
Part of it can be blamed on him. Garp's status as a high-ranking marine made it so that he was rarely home, and when he was he subjected them to Training from Hell to make them strong marines. When they still reaffirmed their dreams to be pirates, he left them with a friend to turn that around. Said friend was a mountain bandit. He was asking for it, really.
The mother from Freaky Friday (2003) also is a therapist, but the relation with her daughter isn't the best either.
The fun comes when it turns out her daughter is a better therapist when it comes to counseling parents, because of her subjective experience from the other side.
We are first introduced to Kevin Spacey's character in The Negotiator as he is failing to persuade his wife to come out of the bedroom in which she has locked herself. Summed up succinctly with this line:
Sabian: I once talked a guy out of blowing up the Sears Tower but I can't talk my wife out of the bedroom or my kid off the phone.
Sophia in Shortbus is a sex therapist/couples counselor who's never achieved orgasm and has a marriage riddled with issues.
In Garden State, Andrew Largeman's therapist is his father. Another doctor lampshades the fact that his father becoming his therapist is a bad idea in general and highly unprofessional of him. This is strongly expressed by the fact that when Largeman was a child, he knocked over his mother in a brief moment of frustration over her depression, resulting in an accident which left her paraplegic, his father jumped to the conclusion that he had anger issues and he prescribed him lithium he didn't really need before eventually sending him to a boarding school.
Cruel Intentions begins with a psychologist who has written a book on the parenting of teenagers. Her daughter has been easily seduced and posed for nude pictures, which are on the web in a parody of her mother's book cover. When she phones Mom in distress, she is put on hold.
The Impossible Years is a 1960s play/film about the home life of a college professor and psychologist who writes materials on family relations. Specifically, on how to handle teenagers (authoritatively espousing a lax parenting style). But he has teenage daughters himself. You can see where this is going.... (And what was the word on the other side of that sign?)
The psychiatrist's family in What About Bob? is highly dysfunctional, thanks to the therapist in question being a domestic tyrant.
Used for a quick joke in The Country Bears; Tennessee's backstory includes a failed relationship with Trixie. So when the band broke up, he became a marriage counselor.
The protagonist in Machine Gun Preacher becomes a hero to children in Uganda when he goes there to build orphanages and ends up rescuing children kidnapped by Joseph Kony's forces, but his wife accuses him of being an absentee father to his daughter back home.
In Thanks For Sharing, Mike is a longterm recovered addict who fully embraces the 12-step philosophy, and acts as a tough but compassionate sponsor/mentor to other recovering addicts. But he's a massive Jerkass to his own recovering-addict son.
In the Harry Potter series, it is often commented how the Weasley family have old and slightly threadbare clothing, due to them being somewhat poor. It is baffling, given the extent and complexity of the spells seen commonly used in this verse, that "tailoring" isn't simplicity itself. Arthur and Molly in particular are shown to be quite skilled at magic, though there are seven kids' worth of clothes to deal with (albeit two of them grown up and on their own by the beginning of the series). It's also hard to see why they can't magic up a bigger, better house.
In L. M. Montgomery's Anne's House of Dreams, Gilbert, being a doctor, is very solicitous about Anne's health, explicitly wishing to refute the proverb "Cobblers' wives go barefoot and doctors' wives die young."
In Charles Dickens's Bleak House, Mrs. Jellyby is heavily involved in charity work for poor children, but neglects her own large family.
In one story about Sherlock Holmes, he and Watson break into house of blackmailer Milverton, which goes horribly wrong. After that Holmes comments, that for all years where he looked for criminals based on small clues they left, he still didn't manage to cover his own tracks.
In Carolyn Mackler's The Earth My Butt And Other Big Round Things, Virginia's mother is a supposed "expert" on teen psycholoogy. However, she has a tenuous relationship (at best) with her own teenage daughter, treating her like the Butt Monkey of the family simply because she doesn't share her parents' or her older siblings' interests or goals. She also frequently verbally berates Virginia for her weight, among other things. In a particularly shameful move for a psychologist, both parents try to block Columbia from prosecuting their son after he date-rapes another student.
In one of James Herriot's books, he describes how the kid singing their Drill Sergeant's bawdy song loudest and with the most enthusiasm turned out to be the son of an archbishop.
The Dresden Files' Molly Carpenter is an extremely sexually active young woman, with multiple piercings and a certain amount of emotional tumult, such that she spends a good portion of the first few books living away from home. Her dad is a devout Catholic, and Knight of the Cross, and takes orders from the archangel Michael. He is rather worried about the direction Molly is going in. She turns out to be a witch. And a Black Magician. And a murderer...
Rachel of Tish Cohen's Inside Out Girl edits a parenting magazine, but when she tries to apply her advice to her own kids, it comes off as cheesy and fake.
The eponymous character of The Picture of Dorian Gray falls in love with the actress Sybil Vane because of her ability to act out Shakespeare's romances. When Dorian invites Basil and Lord Henry to see her play Juliet her acting is terrible. Her only experience with romance was in the roles she played and they could never compare to actually being in love.
The Hunger Games: Katniss assumes that Peeta, being a member of the merchant class and the son of a baker, hasn't known hunger the way she and her family has. She's surprised to find out that despite his family baking for a living they rarely get to eat any of the bread themselves, only the stale loaves they can no longer sell.
Live Action TV
In The Complete Guide To Parenting, George Huntly (Peter Davison) is a professor of child psychology who is absolutely useless at parenting his seven year old son.
Being a psychologist, one would figure that Frasier Crane would be able to deal with his curmudgeonly father and persnickety brother and to find a woman who would make him happy, but noooo...
Eventually, Frasier actually does seek therapy from his Harvard professor/mentor, after the man demonstrated that Frasier couldn't help himself by having him roleplay calling in to his own show as himself.
For bonus points, Frasier's brother is also a psychiatrist, who spends the first few seasons trapped in a loveless marriage, while pining for his father's physical therapist.
An episode of How Clean Is Your House featured a professional cleaner whose own house was the dirtiest Kim and Aggie had ever seen.
The therapist on the HBO series In Treatment has his share of parental issues, as well as being recently divorced.
The overarching plot of the short-lived series Miss Match was that a woman who was both a matrimonial attorney and a professional matchmaker couldn't handle her own relationships well.
In Monk, Dr. Charles Kroger has a terrible relationship with his son Troy. In the episode "Mr. Monk Gets a New Shrink", it's revealed that Charles has taken three paternity tests at the "request" of his son. Troy also calls his parents by their first names, and it turns out that Lieutenant Disher has arrested Troy once before (Troy responds "no" when Randy asks him if he's stayed out of trouble).
Closer to the gist of the trope, Monk solved many, many cases, but was frustrated that he couldn't figure out who killed his wife.
The finale revealed that Monk was unable to solve the murder due to a lack of evidence. And once he did solve the murder and get all the dangling threads of his life cleaned up, his OCD became less excruciating to bear.
Emerson Cod, from Pushing Daisies is a very competent Private Investigator, even when he doesn't have a certain pie maker helping him. He still isn't able to find his missing daughter, though.
In the series finale, the Narrator reveals that Cod's daughter comes to him, and it is suggested that she found him after reading his pop-up book, "Lil' Gumshoe", which he wrote for that specific reason.
Tony Soprano's therapist on The Sopranos is divorced and goes to therapy with her ex-husband and college age son. (This actually makes a lot of sense; dealing with other people's problems constantly must make you want to unburden yourself as well. Apparently, a lot of therapists do this.)
Brenda's family and therapist parents in Six Feet Under, although arguably half their problems are caused by the fact that they are constantly psychoanalyzing each other.
The team in Criminal Minds are brilliant criminal profilers, but have massively messed-up personal lives. In fact, the two members of the team who are probably the least messed up? They're the two who aren't actually profilers. The team do have a tendency to profile each other, but while they're great at deconstructing other people's behavior, they miss the emotional signs of those around them. Hotch was unaware of his wife's growing displeasure with his absence from her and their son's life, though it was quite obvious.
Ben in My Family has a recurring problem with treating his own family, as seen in this hilarious conversation with his assistant:
Brigitte: I think it's a disgrace you can't make any time for your children. It's like the story of the cobbler's children who had no food. Ben: No, it's the story of the cobbler's children who had no shoes. Brigitte: That makes no sense, their dad was a cobbler. Ben: Let me tell you the story of a dental assistant who had no job.
LOST subverts this in a very odd way. Jack, a spinal surgeon, needs his appendix removed... on a desert island... with the bare minimum of equipment (they have chloroform and ether on hand for anesthesia, and they use sewing thread for stitches). He has a dentist and an OB/GYN to help him who could do the surgery for him, but he fervently believes that he should be awake and do it himself. He ends up in so much pain that they knock him out and do it for him.
Similar to the above, in the Poorly Disguised PilotVirtuality, the ship's medical officer discovers he's in the early stages of Parkinson's disease.
On Buffy the Vampire Slayer, Willow's mom cites many statistics and social movements related to young people, but seems unable to view her own daughter as an individual unique from anyone else.
From the Buffy wiki, Sheila Rosenberg "had also been involved in co-authoring material regarding problematic adolescent behavior."
The Middleman: Similar to Willow's mom is Lacey's mom, Doctor Barbara Thornfeld, MD, PhD, a globe-hopping humanitarian who hobnobs with politicans and statesmen while trying to solve the world's problems. Consequently she's simply unable to time with her daughter, and according to Lacey, only calls once a year "to rationalize forgetting about my birthday."
On Firefly, Inara is a "Companion" who has no problem sleeping with her clients, or with firmly refusing Mal's advances. But as soon as Mal gives up on her and spends a night with another prostitute instead, Inara breaks down in tears.
Emma from Glee is the extremely OCD high school guidance counselor... who can't come to terms with her own mental disorder.
There was an episode of What I Like About You in which Val was trying to get a client for her PR firm, a woman who had written a parenting book. Inevitably, when Holly meets the woman's own teenage daughter, she has just bought a box of home pregnancy tests.
On ER the treatment of Mark's father causes a temporary rift between himself and Elizabeth. Elizabeth does not think Mark should be treating his own father and Mark wants his father to live at home rather than go into a hospice. Mark's father doesn't want to stay either but has mixed feelings about palliative care anyway. In the end, Mark prevails and his father dies at home.
Leonard's mother on The Big Bang Theory is a brilliant and world-renowned psychologist and parenting expert who treats her family very, very badly. He confesses to Penny in one episode that he built a hugging machine when he was a child just so he could feel like somebody loved him. Her other children also suffered from the lack of affection/birthday celebrations/Christmas celebrations etc. and whenever one of their accomplishments, personal or professional, is brought up she doesn't express any pride or joy because they aren't her accomplishments. Then there is her husband who borrowed the aforementioned hugging machine and was mentioned that the only times in the marriage that they had sex was to consummate it and for reproduction, granted that he has never actually appeared but his having an affair would indicate that this arrangement was largely her choice and then the likely lack of affection that plagued the rest of the family. It is all played for laughs but all evidence indicates that she was/is EXTREMELY emotionally abusive and/or neglectful to her entire family despite being a world-renowned psychologist and parenting expert.
Keep in mind, there are enough hints to suggest that Leonard is actually the subject of a long-running experiment, detailing the psychological impact of depriving a child of any and all maternal affection. She mentions having written several books on their relationship already, such as Needy Baby, Greedy Baby.
Detective Kate Beckett in Castle is a brilliant and successful homicide detective who is, at the beginning of the series, nevertheless completely unable to make any headway in investigating her own mother's murder and locating the persons responsible, and it's been in large part due to the help she's received from Richard Castle in investigating it over the series that she's made any headway thus far. Justified both in that Beckett tends to suffer from tunnel vision and emotional compromise whenever her mother's case comes up, and that little we've learned about it so far indicates that it's only a smaller part of a very deep and tangled thread of conspiracies surrounding someone who is both very good at and very determined to make sure they never get uncovered.
In Season Two, she found the killer, but he was just a hired assassin and she was left with no idea who hired him. By Season Five, she found the guy who hired the killer, but had no evidence that would be admissible in court, and couldn't even tell her boss how she found him. Sometimes this trope overlaps with Status Quo Is God.
Ellie Brass, the estranged daughter of CSI Crime Scene Investigation Police Captain Jim Brass, is a petty conwoman, a drug addict, a drug mule and, in later seasons, a lowlife prostitute. This culminated when she faked her own kidnapping, nearly killed CSI Brody who was serving as bait for the kidnapper (who Ellie killed), and finally killed her own mother/Brass' ex-wife — not that she wanted to, but because she would have recognized the kidnapper as Ellie's boyfriend. Not helping Brass' case is the fact that when the kidnapper made him choose between Ellie and Brody, he chose Brody. Ellie is, amazingly, not dead despite Brass being the one to confront her after she shot her mother; he is currently trying amend his past by reaching out to a young prostitute who reunited with her father who unfortunately was the victim of the week.
On Common Law, the main characters have to see a new couple's therapist but are not thrilled to discover that the guy is in the middle of an extremely nasty divorce. When they initially overhear him on the phone with his wife, they assume that he is one of the patients.
In Scrubs, Turk suffers from several unusual symptoms for a while, but doesn't take it seriously until Molly Clock asks him how he would diagnose someone else with the exact same symptoms. Turk replies that it sounds a lot like the patient has developed diabetes. He goes to be examined and does have it.
Also occurs with Dr. Cox and his daughter infant Jennifer, who is born with a serious medical condition that required prenatal surgery. When she requires a shot, Dr. Cox doesn't want to be the one to give it to her because he doesn't want her to associate him with pain, and instead walks around for hours trying to find someone he trusts to do it.
One episode has a pediatrician mention that parents of sick children have it worse if they're doctors, as the parent will always want to try to diagnose the child and will worry a lot more because they've "seen too much".
They also have this with Ben, Cox's best friend/brother-in-law, who is diagnosed with Leukemia, but continues Walking the Earth for two years instead of seeing a doctor. It's because of this that he dies, when he returns in season 3.
In the pilot episode of Clarissa Explains It All, Clarissa mentions that her father is an architect who designs oddly shaped (albeit creative) buildings. She then noted how lucky her family was to not be able to afford to live in any of the buildings he creates.
Midsomer Murders: one episode had a psychologist who was completely unaware her three teenage children were sociopathic murderers who'd started by making their father's death look like an accident.
Michael Westen from Burn Notice regularly insinuates himself into the life of the villain of the week, be it a crime boss, drug dealer, Government agent, contract killer or anything else, and draws them into an elaborate web of deception. However, even the most benign attempt to fool his mother always falls flat.
There was a contestant on The Chase who had apparently wrote a book about how to win game shows. He lost at the personal chase and didn't even manage to get more than a few questions right in the cash builder. Best not to think about what must have happened to the sales of said book afterwards.
In Grey's Anatomy, Alex's younger brother requires surgery. He's unable to do anything and begs Bailey to perform a pro bono surgery, which she agrees to.
Meredith and Lexie's father is an alcoholic who ruined his liver because of it. The problem was too bad to fix, so he needed a liver transplant. Because of his alcoholism, he wasn't allowed on the transplant list, so Lexie begged Meredith to donate part of hers. Meredith's stepmother dies from a disease that Meredith incorrectly diagnosed.
Arizona chastises a friend for not going to see her when he first found out he had cancer. Like the Scrubs example above, the guy gets treated too late and dies.
Meredith's mother died as a result of Alzheimer's Dementia (early onset, which she got before Meredith became a doctor). Derek, a neurosurgeon, doesn't want the same thing to happen to Meredith so he arranges a clinical trial to research the disease, which has Dr. Webber's wife as a participant. Unfortunately, Meredith invalidates the trial by messing with the data, while Adele Webber gets progressively worse and eventually dies.
The New Adventures of Old Christine: Matthew becomes a therapist during the show, but their family is extremely dysfunctional. He and his sister Christine are a bittoo close, she is very self-centered, and they both have a screwed up relationship with their mother, among many other things. He lampshades this,note (just as Old Christine's ex-husband Richard is saying that New Christine, who he wants to get back together with, hating him is a good thing) saying that the amount of crazy in that house was too much for him to fix.
Dr Dibbs from Doc Martin is stunningly incompetent in treating herself, on a massive amount of self-prescribed medication and having missed an almost fatal diagnosis. She's barely any better with her patients.
Given that she spent over 20 years working as a nurse without any problem, it's heavily implied the only reason Dr Dibbs is such a nervous wreck is because her husband pushed her to become a Doctor and she cracked under the pressure.
Skins: Leon Levan is a life coach and motivational speaker. One of his sons has been thrown out of the house and now lives the life of an aimless drifter, and the other one feels as though he is imperfect, the inferior son and finally ends up destroying their kitchen.
The trope is used as a metaphor in Harry Nilsson's "Mr. Tinker". Mr. Tinker is a tailor who is unable to "fix" his life.
In Zits, Jeremy Duncan's mother is a child therapist, but much of the strip's humor revolves around her inability to get her teenage son to communicate with her.
Discussed in Peanuts when Peppermint Patty and Marcie debate about how the judges for a skating contest can be qualified if they themselves can't skate.
Marcie: The world is full of unmarried marriage counselors.
One Dilbert strip had Dilbert attending an economics class. The professor has already prepared a presentation explaining why he has to dress like a flood victim despite being an expert on money.
In WWE, Isaac Yankem, D.D.S. was Jerry Lawler's personal Depraved Dentist; however, he didn't take very good care of his own teeth.
In Footloose (the stage version at least) the main character lampshades this by quoting the phrase in reference to the behavior of the local pastor's daughter.
In Zone of the Enders: Dolores, i, James runs into the author of the fatherhood book that's helped him get back together with his estranged children (more or less), just in time to see him have a panic attack as his own son busts out of jail looking for him.
Common problem in MMO games, the healer gets so focused on keeping the other characters alive that they forget their own health, often resulting in someone repeating the page quote.
Even more common in MMOs where the healers and buffers don't even have the ability to heal and buff themselves. But in that case, it's expected.
This is somewhat averted in the Cataclysm expansion of World of Warcraft, where holy paladins gain a talent that causes them to automatically heal themselves whenever they heal any single target.
It also happens in RPGs where you can tell a healer to automatically heal other characters. As a result the AI focuses on the others first and neglects their own health.
In Fire Emblem, healers (clerics, monk, sages, druids, bishops, etc.) couldn't use their staves to heal themselves. This was fixed in Radiant Dawn, where units equipped with a healing Staff automatically recovers hitpoints each turn.
In Persona 4, Sayoko Uehara develops past her nurse side after a former patient of hers dies. Unfortunately, she develops into a Workaholic instead. After she collapses, one of the options you can say to her is the page quote.
In addition, the one case Detective Ryotaro Dojima is unable to solve is the identity of his wife's killer. He feels wracked about it as the incident broke his daughter.
Hugh Darrow from Deus Ex: Human Revolution, the man known as the "The Father of Tomorrow", inventor of modern human augmentation, author of countless books about transhumanism and one of the most powerful, influential and beloved people in the world... has to walk with crutches, as he of all people suffers of an extremely rare genetic condition that causes his body to violently reject augmentations. There is just something so tragic about seeing an old man forced to watch all of his dreams of a better humanity coming true and knowing that he would be the only one not to enjoy the paradise he has created.
It becomes less tragic, or at least less sympathetic, when he tries to kill off a good chunk of the world's augmented population out of jealousy.
Even more so once Fridge Logic sets in: Sarif Industries is developing a "historic" treatment that would remove the need for Neuropozyne and would bypass any and all tissue rejection issues, thereby making his orchestration of the Panchaea incident self-defeating at best.
If team shrink Kelly Chambers survives the events of Mass Effect 2, she shows the most trauma of the NPC crew. In the third game, there's still too much emotional trauma to consider returning to the Normandy. A therapist with crippling Post Traumatic Stress Disorder. And if you botch your interactions with the character badly enough, they will be Driven to Suicide.
In Trauma Center it is repeatedly quoted that "doctors cannot operate themselves".
In Something Positive, Jason's father is another psychologist who can't relate to his own family. Or in this case, he apparently tried to relate to them by using his knowledge to manipulate them into acting the way he wanted, if Jason is to be believed.
In Homestuck, Rose is constantly trying to psychoanalyze her friends and their family issues, yet dismisses her own mother's sincere-if-overblown gestures of affection and attempts to connect to her as spiteful.
There are dozens of articles online titled things like "Reasons to Date a(n) X," with different occupations. One such, entitled "20 Reasons to Date a Writer," annoyed an actual writer so much she actually took to her blog to shred the whole idea, citing this as a reason, namely if a writer is getting paid to write, he or she's not going to waste good material on you for free. Similar articles exist citing such things as a chef not wanting to cook when they get off work and the like.
Reverend Lovejoy's daughter Jessica is a bratty, manipulative hellion who steals from the church collection plate. Near the end of the episode Jessica keeps mentioning things she did ("Remember the glee club brawl?!") in a baldly obvious attempt to win her father's attention, as he tries to ignore her by covering his ears and singing "Bringing In the Sheaves" loudly. Mrs. Lovejoy is characterized throughout the series as an excessive busybody and Moral Guardian who frequently justifies her pushiness and interfering in the affairs of others by protesting "Won't someone pleaseThink of the Children!?"; while she seems excessively concerned with how other people are raising their children, she's apparently not that good at raising her own...
In "Children of a Lesser Clod," Homer becomes a Friend to All Children after he spends a night watching over Flanders' kids and sets up his own daycare center as a result. He then proceeds to neglect his own kids, forces them out of their bedrooms, and makes them work long hours for the benefit of both him and his daycare. Bart and Lisa eventually retaliate by showing all the parents of Springfield just how unreliable and abusive he can really be.
In the Batman Beyond episode "Payback," the high school counselor has little time for his own son.
Braceface had an episode where Sharon wanted to get a tattoo and her mother, a family councellor, wouldn't let her. While her mother is running a seminar on trust between parents and children and how to use that bond to protect your kids from making bad decisions, she uses 'convincing' Sharon not to get a tattoo as an example. An assistant then comes in and informs her that her daughter was sent to the hospital after passing out in a seedy tattoo parlour.
Historical example: Jean-Jacques Rousseau (1712-1778) wrote a lot of material on innovative ways of child-rearing and education, mostly centered around the concept of the child as an unspoiled creation of nature who should not be tainted by science and reason and civilized norms, but allowed to develop naturally. Also, he had five children (with a woman he did not marry), all of whom were immediately after birth placed in an orphanage and never heard from again... which somewhat puts his knowledge on child-rearing into doubt.
Charles Schulz, who went on to create Peanuts, was said to have very bad haircuts as a kid, in spite of the fact that his father was a barber. The reason for this is said to be that he could only get a cut when the barbershop was empty, and when a customer came in he had to get out of the chair and wait before his dad could finish working on him.
The wife of 2010 FIFA World Cup Final referee (and police officer by profession) Howard Webb has said (albeit light-heartedly) that in the family home, he's useless at upholding discipline: "He can't take charge of his own children. I don't know how he manages it on a football pitch."
In the Australian code of ethics, mental health professionals are obliged to seek treatment for any psychological issues they have themselves, whether the issue be an actual disorder, a drug addiction, or just a very high stress level. In the healthcare profession as a whole, self-diagnosis is considered bad form (because it's all but impossible to be completely objective about one's own body). There's also the hypothesis that dealing with crazy people and their problems on a regular basis can drive someone nuts themselves.
If you live with a handyman of any sort you know to expect anything that's not working right to stay that way for a long time. The main reason being that they are often busy fixing things for other people that pay them for their services and the house projects keep getting pushed farther back on their 'to do' list.
There are idioms and sayings about this phenomenon in many languages. In Spanish-speaking countries, that would be "En Casa de Herrero, Cuchillo de Palo" (In the blacksmith's house, there are wooden knives). Another would be "Farol de la calle, oscuridad en la casa". (Streetlight outside, darkness inside)
There is a logic puzzle that depends on this: in a town with two barbers, half the townsfolk (including one of the barbers) have impeccable hairstyles, the other half (including the other barber) look like their hair was the lovechild of Chewbacca and Medusa. The barber who gives good haircuts is the unkempt one. Since he can't cut his own hair, obviously he went to his colleague for a haircut, and vice-versa.