I've been watching Death Note and in Episode 14, Yagami Light refers to Misa as Misa-chan.
In this episode, Yagami meets Misa. They're going to be combining forces, but Misa adds a condition that they be boyfriend and girlfriend. Yagami is not happy about this. He tries explaining that he'll have to be dating lots of girls. This annoys Misa. It's at this point that he calls her Misa-chan and tries to calm her down. Yagami's partner hears this and comments "chan ka yo?".
So I was wondering, is Light being condescending to Misa (afterall he is rather annoyed with her) or, in this context, since she wants him to be her boyfriend, is he playing the role? Would a high school boy call his girl friend using "chan"?