Usually, when you have something that people know it typically happens, and it does happen, the event will just be boring, predictable, and it won't spark anything. For example, like what FAX said (But with a modification), if there is a main male character and a main female character that are deeply involved, they'll most likely have some romanticism along the way. It's natural...but, at the same time predictable. It's not as accepted as well as someone using a sword or a male hero per se.