Because you like Tommy DeVito in Goodfellas

Chuck Bartowski is a sweet, laid-back electronics store/top secret government employee. See them in Chuck.

Helena is a mentally unstable, childish, and completely merciless. And most of all, she's an unstoppable killer. See them in Orphan Black.

Despite the war-torn world around him, Mal Reynolds still holds onto the shred of hope that life can be more than just living another day. See them in Firefly.

Give in to the dark side with vampire Lestat; it's more fun. See them in Interview with the Vampire: The Vampire Chronicles.

Harry Osborn is the privileged son of Oscorp's founder with a goblin-sized chip on his shoulder. See them in Marvel Cinematic Universe.

Point the fun-loving Pippin Took towards second breakfast, and he's one happy hobbit. See them in The Lord of the Rings.

After Rintarou Okabe develops the Phone Microwave, some of his fantasies start to seem uncomfortably real. See them in Steins;Gate.

Egon Spengler prefers collecting spores, molds, and fungus to interacting with people. See them in Ghostbusters.

Andy Bernard is a preppy Cornell grad who's very likely to break into an acapella performance. See them in The Office.

Sometimes being a supportive girlfriend like Ophelia doesn't work out too well. See them in Hamlet.

John Yossarian is trapped in irony as he must be insane to leave the war but if he does try to leave, he'll be deemed sane and will be forced to stay, See them in Catch-22.

A devoted butler, Alfred Pennyworth is both a fiercely protective guardian and a lethal gunman. See them in Gotham.