Because you like Eric Foreman in House M.D.

Whether it's a companion he’s failed or lingering guilt from the war, the Doctor can never truly let go of his past lives. See them in Doctor Who.

Pengiuns, turtles, and all things scientific is where Sam's expertise lies. Girls are uncharted territory, but Sam is trying to branch out. See them in Atypical.

Jenny Flint is a devoted wife and daring crime fighter, which is pretty unconventional for a Victorian maid. See them in Doctor Who.

Kate Beckett is a no-nonsense policewoman with a nerdy side. See them in Castle.

Khan Noonien Singh is super strong, super smart, and out for revenge. He always seems to be two steps ahead of his enemies. See them in Star Trek Into Darkness.

Ianto Jones' withdrawn nature conceals his emotional pain. See them in Torchwood.

Greg Lestrade is gruff, loyal, and quietly competent. See them in Sherlock.

Gilderoy Lockhart's biggest idol is himself. See them in Harry Potter Series.

Jessica Davis is the girl that guys like to like. See them in Thirteen Reasons Why .

A Silurian lizard woman, Madame Vastra has a penchant for puzzles and interspecies romance. See them in Doctor Who.

All of Tate Langdon's obsessions are dangerous. See them in American Horror Story.

This power-hungry Time Lord calls himself the "master of all." Bonus: he has 13 lives. See them in Doctor Who.