Because you like Lily Aldrin in How I Met Your Mother

The vampire that killed Zero Kiryu's family also infected him, and he starts to crave blood, much to his horror. See them in Vampire Knight.

Rainbow Dash's interests include flying, playing pranks, and generally being themost awesome pony around. See them in My Little Pony.

Jane Smith is a stone-cold killer, but you would never know it from looking at her. See them in Mr. & Mrs. Smith.

Catherine Linton was once spontaneous and rowdy but ever since marrying the wealthy Edgar, she has morphed into a boiling pot of emotional outbursts. See them in Wuthering Heights.

Holly Golightly spends so much time trying to be other people's dream girl, she doesn't really know what kind of girl she actually is. See them in Breakfast at Tiffany's.

Hannah Horvath is kind of a mess, but she owns her messiness in a way few people do. See them in Girls.

Resourceful and pragmatic, Selina Kyle always keeps in mind her number one priority: herself. See them in Gotham.

Bridget Jones is a wanton sex goddess, struggling 30-something, and semi-hot mess. See them in Bridget Jones's Diary.

Hoban Washburne shows you can be a hotshot space pilot *and* play with dinosaurs. See them in Firefly.

Mike Ehrmantraut is rutheless, merciless, and probably the most endearing hitman you've ever met. See them in Breaking Bad.