Because you like Ellis Boyd "Red" Redding in The Shawshank Redemption

Optimus Prime is a shapeshifting sentient robot leading a team of robots to stop evil from taking over. See them in Transformers.

Running away from murderous aliens has turned into an interstellar chase for Jupiter Jones. See them in Jupiter Ascending.

Teddy Sanders loves his frat brothers so much he might never leave school. See them in Neighbors.

In his transformation from hardened convict to moral paragon, Jean Valjean is the kind of man we should all aspire to be. See them in Les Miserables.

Gollum is slimy and seething with hatred, the last person you would want to meet in a dark cave. See them in The Lord of the Rings.

Suzy Bishop is only 12, but her withering stare and withdrawn personality are enough to make anyone wilt. See them in Moonrise Kingdom.

Jack's big imagination is never limited by his incredibly cramped surroundings. See them in Room.

Michael Kelso gets by on his good looks and his openhearted nature. See them in That '70s Show.

Wolverine is a hot-blooded Canadian with an adamantium skeleton who's the best at what he does. See them in X-Men Series.

Faith has a chip on her shoulder and a stake in her hand to slay vampires in her town. See them in Buffy the Vampire Slayer.

Homer Simpson is a beer-loving disaster in charge of nuclear safety in Springfield. Everybody run! See them in The Simpsons.

As a monster-hunter cursed with supernatural abilities, Geralt of Rivia is a cynic burdened by scruples in an unscrupulous world. See them in The Witcher.