Some films have so much story to tell that they actually feature multiple plots. While the main plot usually garners the most attention, the remainder of the film's screen time is devoted to less important storylines known as subplots.
Usually, subplots are subplots for a reason. They often don't hold a candle to the main storyline, and are there just to add a little extra flavour to the overall film. Many could be removed from the story entirely without affecting the film's primary story too much, and some lead to successful spinoffs in which the sub plot acts as the main storyline.
However, sometimes, sub plots outshine their film's main story. Often involving the most interesting side character, the most inspired story element, or the most thematically rich moment in the film, many subplots manage to become their film's defining features, rather than the main story.
While not every sub plot would work as the main story, many on this list would improve their films if they were more than just a subplot.
Richard C. Kraus (Richie to pretty much everyone) is an American college student and world record holder for most views of the 2015 film Ant-Man. He has ambitions to someday be a screenwriter, actor, and not tired.