Hm. I apply the rule of understatement to most things. Not that I think about it much, but I definitely do.

So "very creepy" is horror-film-esque. "A little creepy" is pretty close to the most disturbing thing ever.

Or, if I were to say, for example, that Bush is the worst president ever, it'd be hard to take that seriously (even though I mean it). So I'd say "Bush isn't exactly doing a stellar job", combining understatement and sarcasm in a devastating... uh... combination.