A storyline where two people meet, like each other, and have no problems is a boring one. To keep a romantic storyline engaging, there must be internal and external obstacles.
The heartbeat of almost every great story, whether on the screen or in the pages of a novel, is the human connection. While "romance" is a specific genre, are the universal threads that sew different plots together. They provide the emotional stakes that make us care whether a kingdom falls or a mystery is solved.
Two people who despise each other are forced to work together, eventually realizing their passion was just misplaced attraction.