You know what hurts?

You’re on the phone, in an automated system and trying to take down notes. You grab a pen while reading information off the bottom of your PC. You reach up with your thumb to click the pen (thus extending the actual writing part at the other end), and prepare to write.

Except the pen is upside down in your hand, and instead of clicking a button, you impale your thumb on the already-extended ball-point of the pen.

Nifty.