I love some kids. I love interacting one on one with curious kids who always want to know more, or who are just out having fun swimming around and such.
I hate going to a mall or something and having hundreds of little brats running around oblivious to the other people who are trying to get from point A to point B without stepping on them. It's a pain in the ass, because they're just stop in the middle of a walkway and start yelling about something or another, and they don't walk very quickly to begin with. Of course I feel that way about many adults too. I like living in a neighborhood right now where I don't have to be as concerned that small humans who aren't mentally developed enough yet to know not to stand in the middle of the road are going to get run over by me.
Oh, and kids of parents who don't teach them any manners or restraint bug the hell out of me, but I think that's partly just really being pissed at the parents more than anything.