The only difference between Romance movies and Horror flicks is the level of interest the girl has in the guy. In both movie genres, the man has fallen in love/lust so far that he can’t stop thinking about the woman all the time and he always wants to see her. The thing that makes it happy or scary is whether or not she responds in kind or keeps trying to avoid him.
Case in point: the movie “Say Anything”. In this classic 1989 romantic comedy, Diane (pretty valedictorian) breaks up with Lloyd (average guy) because her father was opposed to their relationship and she had received a scholarship to go study in England. Lloyd came to her house in the middle of the night while she was sleeping and held a boombox over his head playing “In Your Eyes” by Peter Gabriel. She didn’t come out to him, but was moved and eventually they got back together.
Now let’s alter one fact about this scene and assume that she has no feelings left for him. It sounds like the beginning of a horror movie: man trespasses onto private property desperately trying to get girl and loudly begs her to come back while playing a love song. Maybe in the next scene he will come back and break in to help her “understand” how much he is into her…
Society says persistence is the key to winning a woman’s heart, but that is only the case if she returns the feelings somewhat. There is a fine line between showing someone who is confused that you like them and showing someone who is confused that you are a freaking stalker lol.