I tend to read text aloud if there is no voice acting, crack personal jokes, say extra bits of dialouge with the npcs (either as myself or as the characters), and call my character an idiot and berate him for doing something when I would do something much different (usually because I think in rather odd ways that game developers probably either wouldn't anticipate or wouldn't bother going through the extra effort for.)
I don't swear at all, and rarely say anything when I am frustrated though.
I don't swear at all, and rarely say anything when I am frustrated though.