Why do you like bad boys/girls?

I've been on a shoujo manga binge and noticed that most of those stories have bad boys as the love interest. This trend is also something you can see in novels and TV shows and films, so much so that it's become a trope that 'nice guys finish last'. Clearly, people must like this type of character, but why?

I personally don't really like that kind of character, but I can tolerate it if the girl isn't too submissive or weak. Maybe because I know what it's like to date a bad boy, and it's definitely not the way that stories portray it to be. But it does make me curious about what other people think makes a bad boy/girl so attractive.

What is it really? I'd love to know.