Or Bad Boys and Why We Love Them
Logan Echolls the character that stole the show in Veronica Mars. Introduced to us by our heroine as the "obligatory psychotic jackass" that every high school has. He starts the show as the ultimate villain to our plucky heroine. I read somewhere that the character wasn't originally one of the main characters, but after you watch Jason Dohring's performance you can see why he quickly became one of the leads.
Logan starts the show not being the most loving character, but we know he can't be all bad since he was loved by our heroine's best friend before the show started. I am personally under the impression that Logan's evolution of character had a lot to do with the chemistry between Jason and Kristen Bell. They start out as enemies, work to wary allies though sometimes still adversaries, to a crucial episode that pitches their relationship to something more. The scene is below and categories the one thing that Veronica could always count on from Logan. He will always be her white knight and will ride in to protect her from the true bad guys. This is the first time, but definitely not the last.
But true to Joss Whedon's simple analysis of ratings: "Buffy happy ratings go down. Buffy sad ratings go up." In this instance, I seem to think it would be "Logan tortured ratings go up. Logan sweet and happy ratings go down." So, Logan has to return to his bad boy ways more often than we can count. Yet, it's revealed that he isn't "bad", but is truly tortured by an abusive father, and because of his extremely loyal and protective instincts he acts out when things feel wrong to him.
Lesson learned from the bad boy Logan.
1) They can be very bad and still be redeemable.
2) You must have a reason for them to be bad other than it is fun, easy, or you just want a bad boy character.
3) Bad boys that our heroines fall in love with are often tortured in their past. A happy past is not allowed. Happy moments, yes, but there must be some sort of tragedy.
4) They can relapse as long as there is a legitimate reason that messes with their heads.
More of Logan coming to Veronica's rescue or defending her in some way.