I've probably done that to someone else a loooooooong time ago (sorry!) but they were rather irritating and I didn't want to block them either. Now I only talk to one person on msn so I don't really have that problem.

I get paranoid at just about everything. If a detail is off, panic! If something seems odd when it really isn't, :s! Watch a scary movie, up half the night. Woo!