It really does sometimes seem like they are just a good outlet for a lot of violent impulses. That, I think, is why there's often a good reason for people to question what exactly the WW will be like without Voldemort because would anyone really want to live under the rule of people like Fred and George? In fact, I tend to think this was a big problem with James being Head Boy--why pick someone that you *know* has a history of cruelty even if he's outgrown it, when surely most of the student body was more normal. It just sends a message that if you put a toe out of line you will be nothing. And like you said, this is up close and personal, it's not even like you're just being crushed by a far away evil dictator.

After all, that's why the chapter called Snape's Worst Memory concerns James Potter and not even Voldemort. Sure he probably faced greater horrors, but I suspect that feeling of helplessness and being nothing never went away. The exchange I linked to above in response to adela sort of gets into that too, for me, that there's always this justification for whatever the twins do when most of the time...why do anything at all? Why do you need to cover someone with boils and why woul you find it funny? It's not that the twins immediately have to become Voldemort or be "evil," it's just that they really are something people should, imo, look at closely because they make it so easy to not think about what they're doing because they're just "having a laugh."