Sex!

A Colonel and a Major are in the BOQ arguing. The Colonel says sex is 90 percent work and only 10 percent pleasure.

The Major argues the opposite: 90 percent pleasure and 10 percent work.

They can't agree, so seek a 3rd party to arbitrate. The only person around is a Private doing latrine orderly duty. They ask him his opinion. He asks them if he could speak freely, and they tell him to go ahead.

He answers, "Well, if you really ask my opinion, I'd say it's all pleasure, for if there was any work connected with it, you'd have me doing it!"