Why do English people have a chip on their shoulder?

It seems like they hate everyone, or they feel like they're above everyone. Listen, I know Americans are notorious for gluttony and narcissism, but unless you've personally encountered a rude and fat American, why do you even give two thoughts about this country? Same with the French and Irish people, or anyone else you think you're better then. I know this is generalizing, but jesus... I go on this site where it's mostly people from England and Canada, and they hate hardcore on everyone else. I've seriously met alot of Americans who are nothing but nice, and try to sway these stupid stereotypes.