Two guys are driving through Texas when they get pulled over by a
state trooper. The trooper walks up, taps on the window with his
nightstick, the driver rolls down the window, and the trooper smacks!
him in the head with the stick.  The driver yells, "Why'd you do
that!?!?

The trooper says, "You're in Texas, son.  When I pull you over,
you'll have your license ready."

Driver apologizes, "I'm sorry, officer, I'm not from around here."

The trooper runs a check on the guy's license, and he's clean. He
gives the guy his license back and walks around to the passenger side
and taps on the window. The passenger rolls his window down, and
smack! the trooper nails him with the nightstick.  The passenger
grabs his face and yells out, "What'd you do that for!?"

"Just making your wishes come true," replies the cop.

"Huh?"  

"Well," says the officer, "I just *know* that two miles down
the road you're gonna say, 'I sure wish that motherfucker woulda
tried that shit with me.'"