When you have mini cricket matches behind the bar you work part time at, using a screwed up piece of paper and a plastic bottle.
Stupid and Obsessive:
Obsessive: When every time someone phones you start practising your bowling with your free hand. Stupid: You have managed to smash the light bulb doing this 5 times in the last couple of months.
Not smash exactly just hitting the shade hard enough for the bulb to stop working.