Ok, here's a joke about the Navy and the Army:
An army officer and a naval officer go into a bathroom and walk to their usual stalls and use the bathroom. As the naval officer was washing his hands, he noticed that the army officer was just walking out without washing his hands.
"You know, in the Navy they teach us to wash our hands after we use the bathroom," the naval officer joked.
"Yeah?" Replied the army officer. "Well in the Army they teach us not to wee on our hands."