I told a friend of a girl that I was trying to game, "don't flatter yourself hun", after she took my being nice to her as me wanting her. She had said something to the tune of how I couldn't resist her, when in fact, I definitely didn't want her. She definitely proceeded to hate me for a while before I told her that I'm usually a lovable asshole, but sometimes mess up the lovable part, and that I didn't mean to hurt her feelings, and to please stop hating. Afterwards all was well, and the girl I was going for asked to see me again. In the context of a girl being too forward, to the point of being out of line (she actually grabbed my junk at one point), is "don't flatter yourself" a little too mean?