Because you like Kelly Kapowski in Saved by the Bell

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

It's hard to tell if Dean Winchester cares more about saving the world or his 1967 Chevy Impala. See them in Supernatural.

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

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.