Because you like Erin Brockovich in Erin Brockovich
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.
What Ron Weasley lacks in motivation and book smarts, he makes up for in loyalty and street smarts. See them in Harry Potter Series.
An escaped convict on a mission, Sirius Black is brooding, brave, and reckless. See them in Harry Potter Series.
Severus Snape is a misanthropic potions teacher with a vindictive streak. See them in Harry Potter Series.
Smart and sensitive Sam Winchester tried to escape the family business, but ghosts have a way of haunting you. See them in Supernatural.
Castiel might be an immortal angel, but the human world is still more than a little confusing. See them in Supernatural.