All Men Are Perverts: Inverted, and probably inverted in the female version of the stage play as well. He's more innocent than even the FEMALE characters, most of whom aren't even particularly lustful. When photographing nudes for Playboy, he's easily able to maintain a businesslike attitude about the whole affair. Meanwhile, Florence is highly resistant to the idea of going on a double-date with Olive and expresses repulsion at her friend insisting that the main point of a typical date is sex.
Ambiguous Disorder: Felix is fastidious, obsessive, man childish, and insensitive without meaning to be. Even when he's trying to be on his best behavior, he finds it difficult to impossible to control his quirks. None of his screen-time ever gives a diagnosis for any of his unusual characteristics.
Animals Hate Him: Averted with dogs but played straight with wild animals. During "I'm Dying of Unger", Felix gets bitten by three animals that we know of — a chipmunk, a rabbit, and a frog — and his bandaged fingers testify to other cases. However, this is only due to his status as the show's Butt-Monkey and not for any lack of innocence on his part. In fact, he's shown to love the animals who attack him, so this could also be considered a subversion of Friend to All Living Things.
Butt-Monkey: Due to people finding his neuroses and obsessive personality insufferable, he's likely to be the butt of the joke.
Camp Straight: He's neat, loves cooking and cleaning, is a stickler for manners, wears his heart on his sleeve, loves opera and ballet, cries at weddings, doesn't like sports, and has some Ho Yay moments with Oscar. Yet, he has an ex-wife that he's obsessed with getting back with, is shown dating various woman throughout the series, and could even be quite the ladies man sometimes!
The Casanova: In some episodes. Albeit in a non-sexual, gentlemanly way, unlike some other examples of this trope.
Characterization Marches On: While the main facets of Felix and Oscar's respective personalities (Felix being a compulsive neat freak, and Oscar being a slob) have always remained intact, their demeanors have pretty much flip-flopped from the movie to the series. To wit: instead of Felix being an uptight killjoy and Oscar being fun-loving and carefree, it's Felix who is more a bright-eyed and easygoing guy (for the most part), while Oscar is more of an irritable, quick-tempered grump (mainly because Felix gets on his nerves so much).
Character Tic / Verbal Tic: When he's upset, Felix presses his hand to his head and "honks" to clear his sinuses.
Classical Anti-Hero: Controlling: Check. Rigid: Double Check. Well-meaning and altruistic: Triple check. Goofy and fun-loving: Check again.
Compressed Vice: In one episode of the series, Felix's nervous tic is not his sinus honking, but his arms stiffening and locking into position to the point that Oscar has to physically manipulate them back into a relaxed position.
Control Freak: Felix has very precise ideas about how things ought to be done and frequently nags others into going along with them.
Crazy Jealous Guy: In regards to his ex-wife Gloria. He goes into a jealous rage whenever she shows - or he imagines she shows - any interest in another man. He once pointed out his jealousy was one of the reasons Gloria dumped him.
The Finicky One: Felix is a neurotic and uptight Neat Freak obsessed with maintaining a healthy lifestyle and a clean enviroment.
A Fool for a Client: Felix always wants to represent himself in court and is nearly always incompetent at it. There is one spectacular exception when he questions an assuming accuser. And even then, Felix doesn't know when to quit until he has angered the judge enough for him to indict both Felix and Oscar with contempt of court.
Friend to All Living Things: Zig zagged. He loves all animals, and a few episodes involve him helping them. However, whether or not they love him back depends on the episode. See Animals Hate Him for more details. Moments where he plays this straight include owning and caring deeply about a pet parrot named Albert in one of the early episodes, rescuing Silver the Wonder Dog from the abusive owner, pampering a grayhound that Oscar won in a poker game, tending to an injured frog, and setting worms free to save them from being used as bait by Oscar.
In the 2015 series episode "The Birthday Party", he receives a pet cockatiel as a present, and seems very happy about it. He remarks that she is "adorable" and "beautiful" and names her Hope. Things quickly go wrong, however.
Heroes Love Dogs: Felix adores dogs (and animals in general), if the fact that he owned one while married, pampered a racing greyhound in "Leave the Greyhounds to Us", and took a dog from an abusive owner says anything.
Heroic BSoD: Felix has one in the 2015 series' episode "The Birthday Party". After having spent his entire birthday party getting over his ex-wife (named Ashley in this version), an old friend of his notices her absence and asks him where she is, proceeding to tell him what a good couple he thought they were and that they looked so happy together, sending Felix spiraling into a depression, which culminates in him returning to the roller skate park where the two first met (on his birthday, no less) in the hopes he'll find her again.
Housewife: Up until her husband dumps her in the female version. Florence tells Olive she used to be a bookkeeper-for her husband, but still. Later on she tells the Costazuela brothers that she used to work but then she "quit to become a mother".
Hypochondria: Felix is a self-confessed hypochondriac, though it's more of an Informed Attribute since every time a doctor is called to treat Felix, it's because he really is sick (typically something allergy-related). The trait is downplayed as the original series goes on, but is dialed back up to eleven for the 2015 revival.
The Idealist: He finds joy and beauty in everyday things, and doesn't hesitate to express it. In one episode, he even writes poems about it.
Incorruptible Pure Pureness: He's one of the most, if not THE most innocent characters on the show. He's shown to always want to do the right thing, and often serves as a moral compass to the others. Even when Oscar tried to get him to lie to help someone, he was extremely hesitant. He DID end up doing it, but he felt so guilty about it that he cried, and later he couldn't stand the guilt, and went and told the truth. There are several other instances where he outright refuses to do morally questionable things.
Innocently Insensitive: Sometimes. He has very high standards, so when someone doesn't meet them, he's quick to point out their shortcomings. Even though he usually tries to be very polite about it, he sometimes ends up hurting their feelings unintentionally.
Manchild: His enthusiasm, excitability, innocence, optimism, and goofy sense of humor solidify him as this. He also occasionally sings or quotes lines from kids' songs, and sometimes throws tantrums when he's upset. The latter is usually his reaction to things involving Gloria.
Men Can't Keep House: Averted, Felix keeps house better than any other character in the story.
Moment Killer: Felix would sometimes arrive home early "not feeling well" and disrupt the romantic mood, much to Oscar's consternation. At the end of "Felix Gets Sick", Oscar pretends he's ill to return the favor but finds that Felix is too nice about the disruption for revenge to be sweet.
Neat Freak: When he was married, his wife would clean the house and a maid would come in once a week to clean some more, but he still felt compelled to get up in the middle of the night and clean everything all over again.
Nervous Wreck: His biggest character trait. He gets stressed out easily by a messy environmental and while it can be pretty hilarious to watch him freak out, it's also pretty sad too.
Nice Guy: He may be a socially awkward dork but he's also friendly, optimistic, innocent, polite, and tries to always do the right thing. Even when he gets carried away sometimes, he seems to genuinely care about the other character's feelings.
The Nose Knows: When Oscar smuggles deli food into a fat farm, Felix can smell and identify every item.... as well as a can opener.
The Perfectionist: Felix is a sophisticated and pedantic perfectionist which can insufferable due to how high-strung and fussy he can be but he's still very sympathetic character, especially in 2015 where his mother puts too pressure on him to be perfect.
The Pollyanna: For the most part. He gets depressed sometimes, but he also tries to look on the bright side, and he always believed deep down that someday, he and his wife would be together again. It pays off in the end, when he and Gloria remarry in the finale of the 70s series.
Sensitive Guy and Manly Man: The Sensitive Guy to Oscar's Manly Man. He loves opera, cooking, and other refined things.
Sickly Neurotic Geek: Especially the TV series which Flanderized his allergies (at first - as the series went on this aspect of the character became less prominent).
Single-Target Sexuality: Towards his ex-wife. Downplayed in the original series, as he still has a few other girlfriends and crushes throughout the series, but he ultimately loves and desires Gloria the most. The 2015 series played this straight — he loves Ashley (his ex wife's name in the 2015 series) so much that the idea of being with anyone else seems to confuse and horrify him — until his neighbor Emily finally confesses her feelings toward him and they become an item in the season finale "The Audit Couple"
Possibly implied in the female version. Whether she's into the Costazuela brothers or not entirely depends on how the Florence actress and director interpret her lines and stage actions around the Costazuelas. Earlier, after Olive shows herself to not belive that Florence is into men in general, Flo struggles to come up with any specific men she finds attractive, finally spurting out "Adlai Stevenson", who was a bald American diplomat that Olive thinks Florence randomly thought of in a vain attempt to convince her that she's into men in general.
Spell My Name With An S: The original play, both films, and The New Odd Couple spell his last name "Ungar" while the 1970-75 series and 2015 revival spell it "Unger".
Tomboy and Girly Girl: Florence is the prissy, tasteful, house-proud Girly Girl to Olive's devil-may-care, unrestrained, can't-keep-house Tomboy.
Oscar Madison (Olive Madison in the play's female version)
Played by: Walter Matthau (stage/film), Jack Klugman (stage/1970-'75 series), Demond Wilson (New), Rita Moreno (US tour and Broadway run of the female version), Brenda Vaccaro (replaced Moreno during the Broadway run of the female version), Matthew Perry (2015 series)
All Men Are Perverts: Although it's not usually explored much due to the series' PG rating, Oscar makes it abundantly clear that his interest in women is decidedly far more than old-fashioned romance.
All Women Are Lustful: In the play's female version Olive pleads to Florence to go on the double-date with her so she (Olive) can have sex. During the final argument Olive expresses anger towards Florence for apparently cleaning up her dirty dreams.
Characterization Marches On: While the main facets of Felix and Oscar's respective personalities (Felix being a compulsive neat freak, and Oscar being a slob) have always remained intact, their demeanors have pretty much flip-flopped from the movie to the series. To wit: instead of Felix being an uptight killjoy and Oscar being fun-loving and carefree, it's Felix who is more a bright-eyed and easygoing guy (for the most part), while Oscar is more of an irritable, quick-tempered grump (mainly because Felix gets on his nerves so much).
Deadpan Snarker: Especially when played by the legendary Matthew Perry.
The Gambling Addict: He's perennially broke due to all the money he loses, so he repeatedly borrows and, on rare occasions, outright steals large sums from Felix.
Guys are Slobs: Oscar's lazy and slobbish nature often gets on Felix's nerves while Oscar gets bothered by Felix's neatness.
Jerk with a Heart of Gold: Oscar is cynical, sarcastic, abrasive, insensitive, hot-tempered, occasionally vindictive and habitually dishonest. The latter is due to irresponsibility rather than malice, however, and under his thoughtless exterior is a loyal, caring, tolerant and very forgiving man.
Lazy Bum: Oscar is lazy and slovenly character who can't be bothered with keeping a neat environment.
Love Informant: Felix falls madly in love with Gloria and wants to marry her, but he becomes such a nervous wreck that he loses his voice before he can propose to her, and he practically begs Oscar to propose to her on his behalf, even going so far as writing down very specific instructions on what to do and say. Oscar, wanting to get out of there, basically cuts to the chase and asks Gloria to marry Felix, to which she agrees.
Men Can't Keep House: Oscar practically never cleans. Surprisingly downplayed some in The New Odd Couple.
Pirates Who Don't Do Anything: Oscar is rarely seen performing his job, which makes sense, since he's a perpetual slacker.
"The Reason You Suck" Speech: Oscar criticizes Felix's perfectionist attitude in one episode, uttering "Felix, the perfect!"
Oscar also calls out others who make Felix upset. In "The Rent Strike", he calls out the other tenants for trying to drive Felix out while forgetting all the things he's done for them and in "The Subway Story", he scalds the insensitive subway riders and says that Felix is the only person trying to improve the situation.
Straw Loser: In "A Grave for Felix", Oscar takes the deposit money for Felix's grave slot to bet on a horse. Said horse started off well, but ended up last, not even getting to finish by the time the race ended.
Tantrum Throwing: Just as an argument is getting particularly heated, Oscar refers to Felix making spaghetti for dinner, and Felix starts laughing:
Oscar: What's so funny?
Felix: That's not spaghetti. It's linguine.
[Oscar grabs the plate of linguine and flings against the wall on the far side of the kitchen.]
Oscar: Now, it's garbage.
Tomboy and Girly Girl: Olive is the messy, devil-may-care, unrestrained Tomboy to Florence's prissy, prim-and-proper, houseproud Girly Girl.
True Companions: For all the frustrations and irritations Felix causes, Oscar somehow always comes through for him. Many times Oscar has kicked Felix out, and he always (eventually) feels guilty about it, resulting in him bringing Felix back. Likewise, if anyone else starts giving Felix a hard time, Oscar is quick (for the most part) to defend his buddy. Tony Randall and Jack Klugman being such close friends in Real Life certainly helped Felix and Oscar's on-screen chemistry as well.
Tsundere: Towards his ex-wife, especially in the 2015 pilot.
Uptight Loves Wild: In a platonic way. Why else would the prim-and-proper Felix stay with the casual Oscar?
Vitriolic Best Buds: Oscar is often cross at Felix for one reason or another, but if anyone else tries to do anything bad to him, Oscar will be on top of them in an instant.
Murray Greschler
Played by Herb Edelman (film), Al Molinaro (1970-'75 series), John Schuck (New)
Ascended Extra: Murray was originally listed as one of "The Poker Players" but he began to appear more frequently as the series progressed, and not only to play poker.
Gag Nose: Murray's nose is the source of many jokes.
Lovable Coward: He tries to avoid violent situations. During "The Subway Story", Oscar tells a joke about how "last night, I saw three cops standing in our lobby. They were afraid to go outside." Murray quickly protests that he was cold.
Sweet Tooth: Murray loves cookies, and Felix often gives him some while trying to get his help.
Ho Yay moments with Oscar. Yet, he has an ex-wife that he's obsessed with getting back with, is shown dating various woman throughout the series, and could even be quite the ladies man sometimes!