^ Exactly
You can ask Superfly or Azathoth (members of a RP I was in before the old guild self destructed), I play a pretty goddamn mean villain ^^;
Does that mean that IRL I go around chopping off limbs, slaughtering villages, and blowing up buildings? No.
But that was my character's role. He was the 'Big Bad'. Sure, there were moments in the RP where others would comment that they actually felt sorry for my character since he had such a dejected past but overall, my character was a homicidal maniac beyond redemption. Jeremiah 'Stonewall' Knox had no reservations when it came to generally fucking shit up, and in the end, the RP was so good that we all still keep in touch to this day. One of the reasons the RP was so fun though, and we all agree, is that I truly played a villain in that RP. I held back no punches and I think I even chopped off another player's arm in that RP (Though I don't remember for sure so don't quote me on that particular detail).
So I played the part. Same thing in this RP. I knew I was going to do a chaotic neutral/evil character so I let him make some morally ambiguous choices that I would never even consider in real life.