Many players bring an aesthetic that I think of as cathartic play to their relationships with their characters . The cathartic playstyle approaches roleplaying as a venue for players to take risks or indulge impulses in ways that might have unpleasant consequences in real life. The satisfaction of cathartic play is the chance to blow off steam.
Consequently, cathartic characters are often similar to their players, but with certain traits amplified and certain inhibitions muted. In a more extreme form of the aesthetic, these characters may be wholly designed around the traits to be amplified. I’ve known people who used short-tempered characters to work through their anger issues; I like to play impulsive people from time to time as a break from my usual overthinkery.
More commonly, however, a cathartic character is simply a version of the player who kicks more ass and isn’t afraid to be a jerk. This milder form of the aesthetic is extremely popular — at its root, traditional “hack and slash” gaming boils down to “It’s us, but we’re killin’ orcs and takin’ no guff from nobody.”