Because you like Scarlett O'Hara in Gone with the Wind

Eren Jaeger will erase the Titans from this world until not a single one remains. See them in Attack on Titan.

A short-tempered guy, Bowser is determined to wreak havoc on the Mushroom Kingdom. See them in Super Mario Bros..

When Rin Matsuoka is not swimming, he mostly spends his time brooding or listening to angry Dubstep. See them in Free! Iwatobi Swim Club.

A crabby troll, Karkat Vantas is perpetually angry about his lot in life. See them in Homestuck.

Insightful about everyone else's neuroses, Rose Lalonde is not as aware of her own. See them in Homestuck.

From his attire to his form while running, aesthetics rule Rei Ryugazaki's life. See them in Free! Iwatobi Swim Club.

He's the great Black Star, and he's come to assassinate you. See them in Soul Eater.

The main priority for Nagisa Hazuki is making sure that everyone has fun. See them in Free! Iwatobi Swim Club.