Ooh, I got one!
Waiting to take a test. Arrived too early, had nothing to do. Also had to endure a nervous teenager tap-tap-tapping his foot - vibrated the whole room and made EVERYONE jittery, little jerk.
I shall forever blame him for my paltry test results.
If you're nervous, chew some gum, punk. (how's that for a one-liner, sir?)