Because you like Kes in Star Trek: Voyager

Castiel might be an immortal angel, but the human world is still more than a little confusing. See them in Supernatural.

His murderous megalomania aside, Loki is quite charming. Just don't mention his strapping older brother; he's a tad jealous. See them in Marvel Cinematic Universe.

A bookish know-it-all with a bossy streak, Hermione Granger always stands up for what she believes in. See them in Harry Potter Series.

A dreamy space cadet, Luna Lovegood has never met a conspiracy theory she didn't believe in. See them in Harry Potter Series.

A wildly brilliant detective, Sherlock Holmes can figure out everything except how to interact with other human beings. See them in Sherlock.