What Sarah brings to the part is her intelligence, at the same time, she's got that hormonal, idiosyncratic goofiness that makes Buffy not just the Terminator.
Joss WhedonAt the end of the day I have many answers for it. It has to do with my mom, who was an extraordinary woman, and a great feminist. It has to do with the people in my life. It has to do with a lot of different things, but -- I don't know! Because I'm not just writing from the female characters for other people. I have a desire to see them in our culture -- that was not met for most of my childhood. Except occasionally by James Cameron. [From the 2011 San Diego Comic Con, in response to being asked why he writes strong female characters.]
Joss WhedonThe Hulk is the most difficult Marvel property because it's always about balance. Is he a monster? Is he a hero? Are you going to root for a protagonist who spends all his time trying to stop the reason you came to the movie from happening? It's always a dance
Joss Whedon