The stuff I don't like...
Easy, common, meme jokes that everyone does
The worse one is that damn one where someone wakes up, groans about being tired, then goes back to sleep. I get that people are trying to "pull from real life" but hell, everyone does this joke and it is not funny.
Trying way to hard to be "relatable" and using "adulting" jokes
Similar to my issue with the waking up joke. Also, I'm sick of dumb jokes where someone doesn't want to "adult" they just want to play Pokemon.
Snobbiness and strawmen
The whole "popular/typical people are stupid but I am different (and better), I [insert geeky thing here]". Sort of like this one (which later was memed).
It makes the artist come off as obnoxious.
Kawaii
This is more of personal taste but I hate gag comics with cutesy anime girls who do cutesy things. There are no jokes, it's just cute. Sometimes it's not always anime girls, I've also seen it in comics with animals or one's about two people in a relationship. "Love is..." is extremely guilty of this.