There are two kinds of people in the world. The kind of person who can look at a collective of traits that are in a character and see what that says about someone, how they act, how they react, what their wants and desires are.

And someone whose only interests ARE those traits. Good writers can take traits and weave a story out of it. Bad writers write to prop up traits. Take Toph for instance: She's IMMEDIATELY introduced as an overpowered god of her magic system. There's no question about it. And yes we learn that it's because she is a nearly self taught guru, but her skill is then very rarely seen as the solution to an episode. No plot asks "Hey, can Toph throw a rock really, really hard?" before it asks "What are Toph's weaknesses." In order right after her introduction, the plots are things like "Everyone gets frustrated at each other and Toph's unyielding nature is a huge thorn in the team's side" "Toph has never taught anyone before and Aang can't catch on" "Toph legitimately fails a fight and feels like shit." And "Toph bristles at anything that reminds her of regiment and order and has to learn to swallow her pride to help her team out." A poorly written show instead would have been like "The team learns to appreciate Toph's blindness." "Toph has to throw a REALLY REALLY big rock to take down an airship" "The team doesn't respect Toph's power enough and they split up."