WMG / Diary of a Wimpy Kid

Greg has begun to start really loving writing in his journals
Two points back this up. First, Greg spends the first two books complaining about having to write in a journal, especially with the hardcovers having the word "diary" written on them, but later stops. Second, the journals began spanning shorter period of time, the first being a year, the next two being half a year each, and now we have weeks condensed into books. Therefore, one can only assume that Greg has loved to do the thing that annoyed him and is trying to squeeze down every bit of his life on paper.

So on the bright side, Greg in universe may be a fledgling writer.

The book is secretly meant to be an in depth psychological study of how a sociopath sees the world at a young age
It would explain why Greg only shows empathy for himself, the fact that his books are spanning shorter periods of times (he wants every bit of his life to be known to the world), and why bad things keep happening. While one could argue that the Sadist Show tendencies are meant to be played for commentary on suburban American life, statistically Greg's life should not really have that much drama in it. Therefore, one can assume that Greg believes the world is out to get him and is making up or exaggerating real world events.

Helping this guess are the movies, which are far less bleak and show all characters (even ones Greg hates) more positively. It also eases some of the Darkness-Induced Audience Apathy the book struggles with if we realize we're meant to laugh at how a self centered person sees the world, like at how we laugh at celebrities prone to Wangst.

Greg is a sociopath
Greg rarely shows empathy for anyone but himself, and almost never feels sorry for all of the obnoxious and/or cruel things he does to people. He also constantly manipulates his family and "friends", especially Rowley, and one gets the impression he only sees them as tools to facilitate his own gratification, for example, he constantly takes advantage of Rowley's childlike mind, tricking him into doing things for him, or taking (or at least sharing) the fall for something that is entirely Greg's fault. Greg also seems to be rather smart for his age, he can read people easily and play on their emotions and personalities. He probably WILL be successful when he reaches adulthood, in Politics or some other field that requires ruthlessness.
  • He has done some nice things, like taking the punishment himself for the Green Blob incident, and trying to play with Manny (though Manny always ruins it by getting Greg in trouble, although they did huddle together in the terrifying tunnel slide at Corny's.) Oh, and he decided to hide the diamond ring so the family couldn't get into a fight over it. As well as that, he's comforted Rowley after a bad breakup, become genuinely angry because a Nice Guy got detention, and is disgusted by two dropouts and their gang stealing thousands of old science projects and papers so they can sell them off to make a quick buck or ruin the awesome Hero Points scheme.

The books are an exaggeration, and the movies are the true story
The books have Greg be less of a Jerk Ass and makes the tales of abuse even more abusive. He also cuts parts he doesn't like (like getting beaten in wrestling by Patty Farrel). The movies are the true story of what happened. Example: In the book, Greg frightened the little children with a worm. In the movie, Greg says that aliens are going to eat them, and abandons them in a construction pit. IN THE RAIN.
  • Actually, he's more of a dick in the book; in the movie he had a reason to do that (He thought a bully from earlier was approaching)
  • Yeah, he's a much nicer guy in the movies - I'd call the movies the exaggeration.
  • Given how many liberties the films take with the source material - not to mention a glimpse into Greg's diary in the Rodrick Rules movie shows Chirag disguised as Holly, which didn't happen in the book - it's more likely that the books and the films (and the webcomic, for that matter) simply take place in alternate universes.

Manny will grow up to become a Psychopathic Man Child Serial Killer
As of book 6, Manny is starting to show an alarming Lack of Empathy and enough boldness to start openly bullying the other members of his family. He's standing right on the edge of Creepy Child territory, and, in light of this, it wouldn't be all that surprising to see him wind up as a temper-tantrum-throwing, thumb-sucking murderer a few years down the line.
  • The first several books do show that Manny's parents spoil him incredibly rotten, much to Greg's chagrin.

The books are actually complex social commentary on the state of America's educational system.
Yes, a teacher not knowing how "jolly" is correctly spelled and an eighth grader not knowing how to carry in math could both be chalked up to Rule of Funny, but some of the events in Greg's school hit too close to home for many students for it all to be exaggeration.
  • Not just the school system. The entire culture of childrearing of today. Think about how Manny is being babied. And Greg's comments on how Rowley's parents shouldn't give him prizes just to feel like winner. And Susan, the Moral Guardian.

Manny is autistic

The whole hot dog issue in Cabin Fever, plus he doesn't seem to be maturing. Not to mention he's young but smart enough to turn off power in the entire house except his own room.

  • Book 7 had possibly shown more evidence, since he's been said to have terrible social skills for his age, and doesn't like playing with other kids and would rather play independently. He also has not one, but almost a dozen imaginary friends. Of course, it's still too early to tell if Manny has autism since many traits between normal and autistic preschoolers are shared and you don't notice any symptoms until later in childhood.

Greg's Dad spent the blizzard in the hotel with his mistress

Dunno, it just seemed odd that he would say he couldn't get home.

Greg (in the movie at least) was the one who wrote on the door

The handwriting on the wall matches up with Greg's. In the book where it shows a cartoon he drew of the incident, this can be easily explained as artistic interpretation. In the movie, however, the only explanation is Greg did it. Perhaps something illicit was brought to the party and Greg imbibed. Under the influence, Greg started to think his brother was a really cool guy and thought it would be nice to write "Roderick rules!" on the door in black magic marker. He has no memory of this event.

Frank (Greg's dad) thinks that Greg is gay and does not approve.

Greg acts really feminine and flamboyant at times; caring for a baby doll as if it were his own child, saying that he'd choose water jazz over swim team, not liking sports and other "manly" things, etc. Perhaps Frank suspects that Greg is gay, and is trying to "stamp it out of him," hence why he throws away said doll without asking, refuses to listen when Greg expresses dislike of sports, tries to send him to military school, and other things like that.
  • This is also backed up by the fact that Frank doesn't approve of the barbie doll Greg gets for Christmas.
Manny is actually a very smart kid.

He's definitely smart enough to know how to work the electricity in the house and appears to know that his mom accepts "I'm only thwee!" as an excuse. He's simply Obfuscating Stupidity and pretends to not be maturing because he knows that as long as he acts childish and throws tantrums, he'll always get his way. Manny, you Magnificent Bastard.

Manny has OCD.

Think of how he wanted his sandwiches cut JUST RIGHT, and how he wanted his hotdog to have the mustard in a PERFECT LINE.

In The Third Wheel Greg and Holly will be an offical couple.
In the third movie that's what happened so it doesn't seem unlikely.
  • Jossed, Holly doesn't even show up at all.

In The Third Wheel Greg's Date To The Dance Will Be Patty
Somehow, he'll either be really desperate or forced into taking her and will have a hilariously terrible time. As consolation, the author will have him hook up with Holly afterward (in line with the above guess).
  • Jossed, he gets a date, but then Rowley steals it from him. Poor Greg.

In a future movie Bryce Anderson will be the main antagonist.
He is featured in the past three books and the third movie ends with Greg and Holly becoming an official couple. Holly herself isn't part of the main plot in The Third Wheel but it is mentioned that she likes Bryce in that book. Now in line with the WMG that the movies are the true events and the diaries are exaggerated, it could be that in the films universe Greg and Holly where not in good terms in their new relationship, so he didn't write her in his diary at the time. If a movie adaption of The Ugly Truth Cabin Fever or The Third Wheel is made Bryce would probebly be a Romantic Rival to Greg.

Holly & Chirag are actually Emma & Ravi.
Chirag's rivalry with Greg over Holly is actually an example of My Sister Is Off-Limits! though it doesn't explain why Holly is quite a bit smarter than Emma.

The Last Straw was supposed to be the last book in the series.
It ends with a happy ending and the last page says in large text "THE END". Furthermore, the next books try to stretch shorter and shorter timeframes into a 200-page graphic novel. Case in point: The Third Wheel takes place over several weeks, yet is just as long as the first book, which takes place over a year. Perhaps someone at the publishing company saw how well the books were selling and decided to make the author write more.
  • Actually, I do remember hearing about something like this.
  • This theory also explains why Trista was put into the series, only to be jettisoned from it at the very beginning of the next book; Kinney had originally not planned on there being a next book; Trista was likely just put in there so that the series would give Greg a Happy Ending even though he didn't get Holly Hills.
  • Its title certainly would indicate it.
  • That was how the orginal webcomic ended, and since the first actual book came out, the author said there would be more after all of the webcomic is covered. So it was most likely planned the whole time.
  • Continuing with the shorter time frames, it'll go from months, to weeks, to mere days, and then maybe the 22nd book will try to stretch out a 60 minute period into a 200 page book.

The series will go on for a really long time.
The series will officially end when Greg and Rowley are in college.

Related to the first theory, Greg has clinical narcissism.
He shows quite a few signs of narcissism, particularly as the books go along. They include but aren't limited to:
  • Blaming all his problems on others.
  • Not caring about others except as a method of personal gain.
  • Not caring or taking responsibility when he hurts others.
  • Becoming seemingly unable to process the embarrassment, sadness, or pain of others.
  • Harming others intentionally and only showing signs of remorse or regret when he's punished.
  • Having no real friends, and only caring about having real friends as a way to make himself feel better.
  • Expecting others, particularly his family, to do whatever he wants without contributing at all.

Greg will be in high school by book 10.
I was thinking about how Greg has to have been in middle school for more years than usual by now. But then it hit me: by the end of the 8th book, Greg is probably in April or May of 8th grade. If you think about it, this means that the 9th book will be about whatever happens in the last bit of 8th grade, and the 10th will be high school. Considering the 5th book is about Greg's aging, he's not just going to stay in middle school forever.

The series will end on a dark note.
Either with Greg killing his family, committing suicide, or both.
  • OK, that's a bit too brutal for a series aimed at primary-school kids. Maybe something more of Greg running away forever would suffice, but not after leaving his journals at school so everyone can read them and see how much his life sucks (in his opinion.)
  • I for one, would rather personally have him move out of the house.
  • Maybe the ending could make it ambiguous as to whether Greg committed suicide or just ran away.

Greg will at least have one wish come true for him-he gets to date Holly Hills (in the books.)
Because really, the guy's a pretty big jerk, but he does need something happy once in a while. Oh, and it could create an interesting situation-all those things Greg did to help out Heather earlier? Well, Heather could have told her younger sister (a few books later) "Hey, that Greg Heffley is a pretty nice guy-he stops me from getting bored with all the cool stuff he says, and he saves me work, too! Maybe you could try and go out with him? I know that he's a dork, but see how it goes!"

The book will have Susan and Frank Heffley and Mr. Jefferson and Mrs. Jefferson start becoming the only sane people. Holly discovers how much crap Greg has gone through and becomes his girlfriend. Rowley gives Abigail "The Reason You Suck" Speech and Manny is sent to a mental institution and Rodrick is sent to jail for two months.

Frankie is Greg's dad
In the tenth book, at a camp, there is a rumor about a madman named Silas Scratch, and the chaperon (who is about the same age as Greg's dad) says that when he was a child a boy named Frankie discovered Silas's shack and was never the same again. Later we find out the shack is actually a shed and Silas doesn't exist, Greg's dad as a kid discovered the shed and lied so the others wouldn't hog it. And we do know Greg's dad is called Frank. The only difference is the "i-e"
  • Really, it was pretty much confirmed that this was the case.

Frank Heffley is not Manny's biological father
Manny's physical appearance looks completely different from anyone in the Heffley family. So it's possible that Susan Heffley might have had a secret affair.

Greg has ADD or ADHD
I have ADD and I've always thought that he had ADD. He displays a short attetion span and is clearly smart but doesn't work hard.

Rowley is better-looking than he is portrayed
Otherwise, the ease with which he wins the sympathy of girls would be puzzling.

Expanding on the above, Rowley is actually something of The Ace
Rowley is actually a kindhearted, friendly, charismatic and talented kid who is slightly naive for his age due to his sheltered upbringing. Greg just plays up his one negative trait and completely ignores his positive ones when talking about him because he's jealous.
  • I regret not thinking about it myself. After all, he had a girlfriend before Greg did, and after he and Greg "broke up" in book 1, he was the first to find a new best friend.

Future books will have some actual Character Development for everyone and good moments for Greg.
Frank Heffley will become less of a Jerkass, Susan Heffley will stop being clueless, Manny will become less of a Spoiled Brat, Rodrick might start heading towards his movie counterpart's personality, and Greg will not only become less of a jerk, but will have some genuine, long-lasting Pet the Dog moments directed towards him, rather than being subject to misfortune most of his life.

Greg is haunted by a bad luck spirit.
It does everything in its power to make Greg's life as hilariously miserable as possible.

Jokes featured in The Getaway
An obvious one with a Screaming Plane Baby, the Take That! to airline food.

The series' final book will involve other characters finding Greg's diaries.
Subsequently, he will have a ton of things come back to haunt him at once, including the water park locker key and the diamond ring.

Greg is planning to sell his journals once he becomes famous
In the first book, he agrees to start writing journals because he doesn't want to waste time answering questions about his childhood when he becomes famous. Some time after that, he realizes something: why give them away for free when he can make more money off of them? This also explains why he stops complaining about his mother making him write the journals, and why the journals began spanning shorter period of time: a shorter timespan per journal means more journals, and more journals means more $$$.