Because you like Al Capone in The Untouchables

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

After surviving consecutive fights-to-the-death (damn you, President Snow!), Katniss Everdeen is thrust to the front lines of a real war. See them in The Hunger Games .

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