Because you like Vada Sultenfuss in My Girl
Bodhi Rook is a defected pilot for the Galactic Empire dead set on destroying the Death Star. See them in Rogue One.
Vash might act like a carefree, peace-loving goof, but it's not wise to underestimate this "Humanoid Typhoon." See them in Trigun.
Phoenix Wright is an easygoing defense attorney who is rarely defensive. See them in Ace Attorney Series .
Bucky Barnes used to be a good-hearted American soldier. Now he's the cold-hearted Winter Soldier. See them in Marvel Cinematic Universe.
Big Boss is a disillusioned mercenary commander who wants to create a world for soldiers (and soldiers alone). See them in Metal Gear Series.
Stuck somewhere between life and death, Talion is motivated by one thing only: vengeance. See them in Middle-earth: Shadow of Mordor.
This power-hungry Time Lord calls himself the "master of all." Bonus: he has 13 lives. See them in Doctor Who.
A devoted butler, Alfred Pennyworth is both a fiercely protective guardian and a lethal gunman. See them in Gotham.
Once a loving family man, James Heller is now dark, damaged, and hell-bent on getting revenge. See them in Prototype Series.
A determined and cold-hearted spy, Cassian Andor will do what it takes to stand up to the evil Galatic Empire. See them in Rogue One.
Stanley Barber is a loveable goofball with impeccable (if eccentric) fashion sense, unique music taste, and a wealth of strange but useful knowledge. See them in I Am Not Okay With This.
It's easy to see why Poe Dameron would side with the rebellion: he's bad at taking orders, likes to show off, and is committed to the cause. See them in Star Wars Series.