I agree with David. In British English at least, this is normally a negative expression, for someone arrogant, self centred, cocky, bumptious ... (a ruder version is to be "up yourself"). Though I'm sure there must be a positive side somewhere. I am reminded of a scene in the film Coming To America, where one brother says to another, "Mother always said you were greedy." To which the other brother replies, "She meant it as a compliment!"