A blonde is speaking to a psychiatrist.

Blonde, Im on the road a lot, and my clients are complaining that they can never reach me.

Psychiatrist, Dont you have a phone in your car?

Blonde, That was a little too expensive, so I did the next best thing. I put a mailbox in my car.

Psychiatrist, Uh … Hows that working?

Blonde, Actually, I havent gotten any letters yet.

Psychiatrist, And why do you think that is?

Blonde, I figured its because when Im driving around, my zip code keeps changing.