Developing the main character is the basis of any good film, but there are dozens if not hundreds of movies where a secondary character outright steals the show.
Iconic roles can usually be locked down to a single face. Indiana Jones will always be Harrison Ford, Luke Skywalker will always be Mark Hamill. There’s a certain special connection you can make between a character and an actor if they become one and the same. There’s loads of iconic roles that have been played by different actors, however.
Supporting characters usually get a bad rep. They’re often dismissed as a necessary evil and characters that hang around for no other reason than to carry the plot forward. Sometimes, however, supporting actors knock it way out of the park. They completely own their character and steal the screen every time the camera’s pointed at them.