I only prank the people that either get on my bad side, are funny when they're angry [ That's you, Aoko! ] need to lighten up, or just deserved it.

Like those girls that continuously found frogs in their lockers-they deserved it. [ for reasons he won't specify but he felt it was well deserved it. ]

...Too bad Hakuba-kun's not here.. he fell into all of those categories.