I once spent a month in prison.

I once spent a month in the slammer.

It wasn't that bad. The guards were friendly. My cell-mate was a cool guy. The food was better than my wife's. I didn't see any fights. I wasn't assaulted or raped.

On my last day a guard walked me out to the exit gate. We chatted about football on the way. As the gate opened he said to me, "Goodbye and good luck. How do you feel?"

"I feel good, man," I replied. "I'm happy to finally be out."

Then he smacked me hard across the skull with his baton, drawing blood. I was like, "What the hell, dude?"

"That's for ending your sentence with a preposition."