Because you like M. Bison in Street Fighter
Rupert Giles is a librarian on the outside, fearless evil-fighter on the inside. See them in Buffy the Vampire Slayer.
Maurice Moss is a dedicated IT guy who even talks like a computer. See them in The IT Crowd.
An intriguing bundle of contradictions, Sawyer Ford trusts no one on the island, and no one should trust him. See them in Lost.
Ponyboy Curtis is a "Greaser" on the surface, but he's a sensitive poet underneath. See them in The Outsiders.
Christine Daae has been secretely taking lessons from a phantom musician. It sounded less creepy in her head. See them in The Phantom of the Opera.
The only constant in Night Vale is Cecil's hypnotic voice. See them in Welcome to Night Vale.
For the sake of science, Kurisu Makise will persevere no matter how deep into the dark secrets of the world she finds herself. See them in Steins;Gate.
Stanley Barber is a loveable goofball with impeccable (if eccentric) fashion sense, unique music taste, and a wealth of strange but useful knowledge. See them in I Am Not Okay With This.
Albus Dumbledore oversees the most unsafe school in recorded history, with Dementors and giant arachnids run amok. See them in Harry Potter Series.