Excellent point that the lack of profanity on this site has to do with the characters. It's part of the package. I know I love that Superman is a good guy and always tries to do the right thing. And in L&C, I always loved the fact they didn't swear and that they even waited to be married before consummating their relationship.
You could argue that TV shows at the time didn't allow such language but it doesn't seem to fit the overall tone of the show.
I used to write CSI fanfiction. I remember having a somewhat similar discussion about the use of profanity on the show and in fanfiction. Many felt it was unrealistic that the characters didn't use swear more. It made me sad when several people in the discussion responded that everyone used those words. They heard them on a daily basis.
Joan
