There's actually some Truth in Television for this trope. Some people are insecure enough that they accept that kind of abuse and feel that they can win the person over or worse yet, they desire it. It's not as funny in real life, though.
It's also not much fun to be on the other side - the character who is put on a pedestal and persisted after. This is why Dogged Nice Guy tropes are often disgusted as being sexist. The audience tends to side with the Nice Guy who persists and whose POV is being told, rather than the character (usually female) who becomes the object of affection.