A veteran walks into a bar, orders a drink, and soon starts a conversation with the man on the bar stool next to him. After a few drinks they discover that they both were in Vietnam.
The first man says, "I was only a helicopter mechanic but I have seen the horrors of war."
"Oh, yes," said his companion. "I still have nightmares about the men I have killed."
"I truly understand. I killed fifteen men in that war."
"Wait a second. I thought you said you were a helicopter mechanic."
"I was, but I never said I was a good one."