"The mention of romance generally elicits a youthful and delighting emotion, but it is subjective by nature. The maturity of a relationship can unearth some shocking truths, which is at times very discomforting for the audience to experience. Also, contrary to the popular notion, romance is often dangerous and destructive by nature, especially when both sides are not equally willing.
In a sad turn of events, a happy romance can also deteriorate with time and become bitter when people can't even stand each other. It is a surprise when a film that is assumed to be romantic or dramatic from the outset changes its nature where the horror tag becomes more appropriate."