We all know at least one. I mean most things I hate in life can be traced back to them. Pink shirts on men...douchebags. Fred...douchebags (A douchebag providing douchebaggy entertainment for the joy of douchebags). The person I hate most in the world was the stereotypical douchebag.
EDIT: And you know the whole "surfer" generation of Australia that spiked up around the '70s. You know, those smelly, good for nothing hippies who read magazines that glorified drug use and an obnoxious foul-mouthed pig while claiming that doing nothing but surfing all day was liberating and not depressing or pathetic. Their the worst douchebags of all!
Oh and people who whine and say "I have no faith in humanity" or "I hate human kind in general". But again that can be traced back to soppy, mopey emoism (Most of the time) which in turn can be drawn back to douchebaggyness. Have you seen the world and what we as a race have acomplished, most of it's pretty good.