I think there was a cloud hanging over the seventh season, especially in the beginning. I don�t think anyone was sure what Sarah was going to do, but I think she decided that seven years was enough.

She�d just got married and I think she wants to have children relatively young. She wanted to spend time with her husband and explore other opportunities, primarily in film. I�d imagine she�ll make guest spots on Angel from time to time, to keep people happy until the Buffy movies start coming out.