Because you like Jennifer Melfi in The Sopranos

Severus Snape is a misanthropic potions teacher with a vindictive streak. See them in Harry Potter Series.

What Ron Weasley lacks in motivation and book smarts, he makes up for in loyalty and street smarts. See them in Harry Potter Series.

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.

L is enigmatic, child-like, and one of the smartest people in the world. See them in Death Note.

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