Because you like First Doctor in Doctor Who
Puss In Boots is a suave, honorable ladies man/cat who's not above playing cute to get you to let down your guard. See them in Shrek 2.
Brilliant, violent, and only a little insane, the Joker doesn't listen to anyone except the voices in his head. See them in DC Extended Universe.
With great power comes great responsibility, but Peter Parker always seems to get the short end of that bargain. See them in Marvel Cinematic Universe.
Castiel might be an immortal angel, but the human world is still more than a little confusing. See them in Supernatural.
Severus Snape is a misanthropic potions teacher with a vindictive streak. 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.
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 .