Sleeping Beauty

This small trick will work when your friend has drifted off to sleep, say, on the bus, in the classroom or at work.

Shake his/her hand violently, waking him/her up, and ask, "Sleeping?" He/she will say something like "Yeah..." And you end by saying something like "Okay" or "Oh."

Do it a couple of times more for effective nurturing of irritation!

Sounds simple but works great!