A saleswoman is speaking to her psychiatrist.
“I’m on the road a lot, and my clients are complaining that they can never reach me. “
“Don’t you have a phone in your car?”
“That was a little too expensive, so I did the next best thing. I put a mailbox in my car. “
“Uh… how’s that working?”
“Actually, I haven’t gotten any letters yet. “
“And why do you think that is?”
“I figure it’s because when I’m driving around, my zip code keeps changing. “
This joke is included in the Black Book of Jokes. You can order it from here.