I like kids before and after the early teen 12-15 years, around junior high school age, at least in America. (One of the ways Japanese kids are different [I teach them]; Japanese junior high kids are great too!) American junior high kids seem to have the obnoxious tendency to be complete dicks to everyone just because they think they can. I have found only two exceptions to this rule: my sister and one cousin of mine. They fail to put anything into proper perspective, flipping out over the tiniest of things and not giving a damn about the stuff that really matters. They rebel far too often, they do horrible things to each other just for the lulz, and they get pissed off if anyone doesn't treat them like the rulers of the world. Once they get past the 15-16 mark, they're fine again. But good lord, those few years before then, they are living nightmares.