Kids, similarly to adults, are each individuals, so I try to give all of them a chance and let them show me how mature or immature they might be. When I was younger, particularly middle school age, I found myself surrounded by adults who all attempted to classify me with the children around me, whom I had little to nothing in common with. As the adult now, I try to give kids the benefit of the doubt.
So in short, I don't hate all children, just the ones that piss me off/get on my nerves/act like little bastards.