Dirty windshields

It was raining, the windshield had mud splattered on it, and the car had almost collided with another vehicle twice. The hitchhiker was beginning to wish that this driver hadn’t picked him up.

“Don’t you think you should wipe off the windshield?” asked the passenger.

“Oh, no,” said the motorist with a smile. “That wouldn’t do a bit of good. I left my glasses at home.”