How to mess with people's heads

Well, as proven by all day yesterday, the way to mess with my head is to tell me that I'm an underachiever. That was a really big way to mess with my head. If you're looking for little ways, here are a few good ideas:
Take my pencils out of my bag and put them all in my locker
Move my shoes from their honorary place by the front door
Get me into states, even if I didn't get to supersession at a turnoment that I got into supersession at last year
Give me coal for christmas
Tell me that I'm ahead on my wordcount

How could I mess with your head? In the comments.