Because you like Moist von Lipwig in Discworld

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

Wise beyond his years, Ashitaka is a dutiful young prince who respects the balance of life. See them in Princess Mononoke.

Violet Parr is an angsty teen would love to become even more invisible than her superpowers allow. See them in The Incredibles.

Stranded on Mars, Mark Watney is armed with quick wits, an electronic diary, disco music, and an undying resolve to make it back. See them in The Martian.

An obsessive schoolgirl, Yuno has two sides to her personality, and both are equally unnerving. See them in The Future Diary.

A level-headed show business icon despite his amphibian status, Kermit is the brains behind the success of the Muppets. See them in The Muppet Movie.

You don't teach a class called "How To Get Away With Murder" without knowing a thing or two about getting away with things. See them in How to Get Away with Murder.

Bedside manner is for chumps, not the brilliant Dr. Gregory House. See them in House M.D..

Twisted and seemingly soulless, Bellatrix Lestrange finds joy in making others suffer. See them in Harry Potter Series.

Aragorn is the one true king, a title he is too humble to accept. See them in The Lord of the Rings.

Pro tip: the psych ward is not the best place to find a mentor like Lisa Rowe. See them in Girl, Interrupted.

Elio Perlman likes the piano, peaches, and his father's new research assistant a little too much. See them in Call Me by Your Name.