The premise of the show, in case you don't know, is this: slighted, angry, and denied her own happy ending, the Evil Queen Regina (am I the only time who gets a kick out of that name, or is that just the nerd in me?)(Regina means 'queen' in latin, hence the kick) curses all of Fairy Tale Land. Everyone's memory is wiped and they're stuck in a time loop in Storybrooke, Maine until Emma, Snow White and Prince Charming's daughter, returns to break the spell. The show alternates between revealing each of the character's histories (and I love, love the twists they've put on all the fairy tale's so far), and what's happening in real time as Emma and Henry (a little boy who knows it's all a curse) work to break the spell.
There are many things I love about this show (not least of which is Josh Dallas) is the well rounded, and sympathetic characters. Most of all, Regina. She has the potential to be an incredibly flat, rah-rah go evil! sort of character. But she isn't. Regina has motive; she's been denied a happy ending over and over again. She's also been wronged by Snow White - in this telling, Snow is no innocent victim of her own beauty. She's an active participant in creating the anger that propels most of Regina's narrative.
It's hard (at least for me) to not feel a little sympathy when Regina is spurned by her adopted son in favor of his birth mother, left by Graham in favor of Emma, turned on by any number of people when all she wants is a happy ending. Her moral compass might be a little skewed, and her methods questionable, but her core is something we all understand and recognize. She wants to be loved, she wants friends, she wants to be happy. But the fairy tale dynamic won't allow her to be happy, without removing happiness from someone else -and that's why we think she's evil. Because we think the cost is too high, even though, had it been Snow working for her happy ending, it would have ended the same, just with Regina on the other side.
I think there's a lot to learn from the writers of Once Upon a Time (and why not, since they're also the writers of Lost), and a whole lot to learn from Regina as a villainess. Cardboard villains are all well and good, but the ones that make and enrich a story are ones we understand, who maybe took a wrong turn, but were on the same path until something awful happened. When we understand and sympathize with the circumstances of their creation, we can love and hate them better, and in that way, tell better stories.