A rancher got pulled over by a State Trooper for speeding. The trooper started to lecture him about his speeding, and in general began to throw his weight around to try to make the rancher feel uncomfortable.
Finally, the trooper got around to writing out the ticket. As he was doing that, he kept swatting at some flies that were buzzing around his head. The rancher said, "Having some problem with circle flies there, are ya?" The trooper stopped writing the ticket and said, "Well yeah, if that's what they are. I never heard of circle flies."
So the rancher says, "Well, circle flies are common around livestock. See, they're called circle flies because they're almost always found circling around the back end of a horse." The trooper says, "Oh," and goes back to writing the ticket. After a minute, he stops and says, "Are you trying to call me a horse's ass?"
The rancher says, "Oh no, officer. I have too much respect for law enforcement and police officers to even think about calling you a horse's ass." The trooper says, "Well that's a good thing," and goes back to writing the ticket.
After a long pause, the rancher says, "Hard to fool them flies though."