There's a famous line which says that you can't have a good hero without a good villain. That may be true, but sometimes the villain can ultimately take centre stage, even when that wasn't the intention.
Whether it's thanks to a stellar performance from the actor, a well written character with an engaging story arc, or whether it's because their surrounding cast-mates drop the ball, there's a whole host of reasons it can happen.
In a debate as old as film-making, sometimes the blank slated "good guy" can come across as boring whereas a villain can be much more intriguing. With complex histories or disturbingly reasonable morale compasses, sometimes the antagonist has a point, and sometimes the character themselves just simply command our attention when they had no right to.
12. Joker - The Dark Knight
If Heath Ledger's iconic performance as the Joker was where your mind immediately jumped too, you wouldn't be alone. He remains a measuring stick for actors and actresses applying their trade to evil antagonists hell-bent on wreaking havoc on a city he feels he has a genuine gripe with, and will stop at nothing to ensure it's done with flair and a sense of the dramatic.
This iteration of the Joker is rich with charisma, making it unsurprising that he has the immediate potential to overshadow other characters on screen, but Heath Ledger's Joker goes beyond that: he's "likeable".
Much like some others on our list, the ticking time-bomb nature of the character leaves you on the edge of your seat. In the blink of and eye - and at the loss of one at one stage ironically - an epic soliloquy rife with compelling narrative can derail into an act of brutal violence, and then back again.
It's the ease and comfort that this Joker embodies that makes him so engaging. Audiences find themselves enthralled by his charming expositions, succumbing to his over the top style, but are equally as encouraged to fight a sense of sympathy for the character knowing full well he has undergone some terrible tragedies in his life.