Why?...because i say absolutely the wrong thing all the time.
Here are some examples:
During a conversation with good friends about what makes a good tattoo, I said something along the lines of "I would never get a tattoo of something like a frog or a butterfly"
Friend 1 answers "I have a frog"
Friend 2 answers "I have a butterfly"
At a bar, my friend's band was playing, and they were great. They took a break, but said they would be taking the stage again. About 30 minutes later, I approach my friend, and try to compliment his band by asking when he was playing again. But the way I actually phrased it was "When are you guys going on again? This DJ sucks"
Friend answers: "This is my iPod mix"