Triviality is a quality of being unimportant or insignificant. You might dislike most reality TV shows because of their triviality, preferring to watch documentaries about serious subjects.
You can also use the word triviality to mean an unimportant detail: "Let's discuss world peace instead of focusing on trivialities like what's for lunch or which celebrities are getting divorced!" It comes from the Latin word trivium, which means "commonplace," but also "crossroads." Literally, it's a combination of tri, or "three," and via, "road." Hence, a trivium is an oh-so-ordinary "place where three roads meet."