Positive arcs show characters overcoming flaws (Luke Skywalker gaining confidence). Negative arcs show characters succumbing to their worst impulses (Walter White embracing power). Flat arcs show characters who do not change but change the world around them (James Bond, Indiana Jones).

Flat arcs are underappreciated. These characters function as catalysts — they are already complete, and the story is about how their presence transforms their environment. The audience's pleasure comes not from watching the character change but from watching them impose their established identity on new situations.