Is it customary to leave someone alone after you use this line? I mean, whenever I say it, I actually mean it. I literally carry on as if nothing has happened, although I'm slightly more wary of how I act around them. However, every time I've remained friends with them, they always seem to interpret as a window of opportunity. Before long, they get all sweet again, but now under the guise of "friendship". They say that they understand we are "just friends", but what they say, and what they do, totally contradict. I'm not the kind of person who would lead someone on, but perhaps I am doing it wrong by staying friends with them in the first place?