A blonde was driving home and got caught in a really bad hailstorm. Her car was covered with dents, so the next day she took it to the repair shop.

The shop owner saw that she was a blonde and decided to have some fun. He told her just to go home and blow into the tail pipe really hard and all the dents would pop out.

So, the blonde went home, got down on her hands and knees and started blowing into her tail pipe. Nothing happened. She blew a little harder and still nothing happened.

Her roommate, also a blonde came home and said, "What are you doing?"
The blonde told her how the repairman had instructed her to blow in the tailpipe in order to get all the dents to pop out.

Her blonde roommate rolled her eyes and said, "Duh! Hello! You need to roll up the windows first!"