Heroics. The fate of the society/world/universe turns on the actions of one or a few characters.

Heroics only make sense in certain settings. In many/most, it really doesn’t make sense for the main characters to be the primary plot drivers when there are millions or billions of other actors in the world. I think it is overused, presents a tunnel-vision worldview, and ultimately confines the world to the characters and ends up less interesting for it.