I accidentally made a rom-com subplot in one of my games... Twice... And the players loved it both times.

The first time there was a divorced smith lady who sort of had a death wish, and the timid tavern owner who had a massive crush on her. Of course the players wanted to set them up.

The second time, the players had to infiltrate a masquerade ball. Sadly I'm starting to forget the details. I think there was tension around meeting them while masked and, like a rom com, trying to figure out what they thought about the PC. And then they tried to get the NPC involved in their heist, because they just happened to have a skill they needed. And of course it wasn't a clean heist, and the NPC had some trauma.