On a couple of occasions I got wrapped up on a buddy's shenanigans.

One was a roommate. He was cheating and bringing his side chicks to the crib, expecting me to run interference when his SO showed up, or if she tried to grill me. I told dude his girl didn't deserve that, and that if she ever showed up while he had a side chick over that I was going to open the door, excuse myself, and go grab some Krispy Kreme.

Another time the wife and I were good friends with another couple, so I was getting questions from my wife about whether my boy was cheating on her friend. That put me in a VERY uncomfortable position. Luckily for me his wife ended up catching him before I had to come clean to my wife, which I was about to do.