Eliezer Yudkowsky said this quote

And then Harry Potter had launched in to a speech that was inspiring, yet vague. A speech to the effect that Fred and George and Lee had tremendous potential if they could just learn to be weirder. To make people's live surreal, instead of just surprising them with the equivalents of buckets of water propped above doors. (Fred and George had exchanged interested looks, they'd never thought of that one.) Harry Potter had invoked a picture of the prank they'd pulled on Neville - which, Harry had mentioned with some remorse, the Sorting Hat had chewed him out on - but which must have made Neville doubt his own sanity. For Neville it would have felt like being suddendly transported into an alternate universe. The same way everyone else had felt when they'd seen Snape apologize. That was the true power of pranking.