Re: But WAIT, there's MORE!
(Ack, I realize now I left a pronoun out of there. "I think he might have a crush on her", rather.)
But yeah, it's true. "Booster" somehow sounds more familiar and comfortable than "Michael". I don't know if I'm just confusing fanfic with canon, but I seem to recall him being referred to as "Mikey" once or twice, which seems to suit him a bit better than Michael.