A blonde is speaking to her psychiatrist. "I'm on the road a lot, and my clients are complaining that they can never reach me."

The psychiatrist asks, "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 mail box in my car."

"Uh ... How's that working?"

"Actually, I haven't gotten any letters yet."

The psychiatrist asks, "And why do you think that is?"

The blonde says, "I figure it's because when I'm driving around, my zip code keeps changing."