In a long line of people waiting for a bank teller, one guy suddenly started
massaging the back of the person in front of him.

Surprised, the man in front turned and snarled, "Just what the hell you are
doing?" 

"Well," said the guy, "you see, I'm a chiropractor and I could see that you
were tense, so I had to massage your back.  Sometimes I just can't help
practicing my art!" 

"That's the stupidest thing I've ever heard!" the guy replied.  "I work for
the IRS.  Do you see me screwing the guy in front of me?"