[johnny]

I do put thoughts and personal feelings of the character into the post, because that sort of stuff does give a (good) roleplayer something to work with. If the character's thinking sarcastically while acting nice and pleasant, it tells the other player that their character should be a little suspect of what my character's doing. It gives a little insight into the tone and personality of the character - not so that the other character can know exactly what's going on, but at least so the other player knows that when that nice-and-friendly character pulls out a knife and threatens the other character, it's not completely out of left-field.