If you're a parent you can totally empathize with this situation.  Every-time my son, Elijah, gets a shot he miraculously gets amnesia and forgets that the last one didn't really hurt, lol.

A mom shot cell phone video of her frightened son as he's being prepped for a shot at the doctor's office. He looks like he's about 10 or 11. He's already in tears by the time it happens, and then is totally surprised when it doesn't hurt.

He's also pretty annoyed at his mom who won't stop laughing at him.