The show is set in San Francisco because creator David E. Kelley wanted a cosmopolitan setting. Previous Kelley shows have been set in Boston (including Ally McBeal (1997), The Practice (1997) and Boston Public (2000)) because Kelley believed it would be easier to get exterior footage shot in Boston if all of his shows were set there (although it turned out to be more expensive).
Lynne, if I can be older and wiser for a moment . . .
Lynne Camden: You can be older.