I'm sure quite a few people would agree that the best thing to come from fandom is the fanart, particularly Shushio's work, IMO. The flashes are nice too, but I like the detail in the fanart better than the movement.
I should be amazed that no one said McRoll yet, but I guess it's just low down on the list, not rock bottom. I'd say yukkuri is worst, in the end.