Because you like Harry Kim in Star Trek: Voyager

How is angel Aziraphale supposed to stop the apocalypse when Hell's forces misplaced the Antichrist somewhere? See them in Good Omens: The Nice and Accurate Prophecies of Agnes Nutter, Witch.

Leonard Hofstadter is the normal one among his scientist friends, though in fairness that's a low bar. See them in The Big Bang Theory.

Disgust is a friend who makes sure you stay away from all things gross. See them in Inside Out.

Donna is boisterous and spunky traveller of the TARDIS, exploring worlds beyond the simple mundane enterprises of Earth. See them in Doctor Who.

Captain Spock is on a five-year mission exploring the final frontier and boldly going where no man has gone before. See them in Star Trek.

A born psychopath, don't expect Michael Myers to understand the difference between right and wrong. See them in Halloween.

Velma Dinkley is all about getting results, not taking credit. She is the unsung hero of Mystery Inc. See them in Scooby-Doo.

It's a race against time to develop his theory of the origins of the Universe before Stephen Hawking's body and mind give out. See them in The Theory of Everything.

A photographic memory is just one of many skills Lexie Grey brings to the table as a surgeon. See them in Grey's Anatomy.

Manipulative, conniving, and ruthless, Mr. Gold is enigmatic no matter what world he's in. See them in Once Upon a Time.

Arwen has to choose between a life of loneliness or love and inevitible death, both rather unfortunate options. See them in The Lord of the Rings.

One of the best in the magical world, Mad-Eye has the battle scars to prove his dedication to such a dangerous job. See them in Harry Potter Series.