I'm fine with younger kids, but the ones who just TRY to annoy you and make you angry piss me off. Like my friends little brother, he knows that if he makes us angry, he won't get in trouble, but we will, even though we weren't doing anything in the first place.
Mentally challenged people, I'm fine with them too, Except for the ones that like, I don't know, try to ruin your homework / something else. Its not like they really have control over it, but it still bugs me. Theres a few at my school. Most of them don't have there.. disease? really bad, but theres one, who growls at us, thinking he's scary. He also screams at us at the top of his lungs. If you so much is lightly 'hit' him, it wouldn't even count as hurting him. Like, When you pet your cat or something, He'll start bawling and go running to a teacher, and then, them having to baby all the mentally challenged kids, have to get you in trouble for trying to get him to move or something.
Fat kids. Fat kids with really high pitched voices make me want to tear my head off and eat it (Wut?) A kid at my school, hes really fricking fat, has moobs, his face is short and fat, and he crys from falling off of a Wave Board, and when you pat his head. He will start screaming at you if you ask him sorta odd questions. This one kid asked him something like "How well can you ride the waveboards in Gym?" and he started screaming things like "STOP TALKING TO ME!" and "GO AWAY!" He'll also try to control what people do.
The reason I brought up the fat kids part was cause I think that he may have a mental disorder. Or something. He couldn't do anything about it, but he COULD do something about being a fatass.
tl;dr: I'm fine with little kids who aren't annoying, fine with mentally challenged people who don't try to purposely annoy you, and I'm fine with fat kids as long as they aren't completely dumbasses.