Harold and Maude (1971)
A young man is obsessed with death. A 79-year-old hippie, free-spirited woman tells him about the joys of living and how to relish in being alive. The chemistry between them isn't necessarily romantic, but it's addicting to watch. After all, being 80 is much closer to death than 20, so she has a thing or two to talk about before she goes.
Knocked Up (2007)
Judd Apatow is kind of the king of romantic comedies. Knocked Up is Seth Rogan's debut and one of Apatow's best works. It follows a couple who had a one night stand and came out of it with pregnancy. Alison (Katherine Heigl) decides to keep the baby, bonding the couple forever.