One of the best Cantonese restaurants in San Francisco, R&G Lounge also has the market cornered on crab. Choose your own live one from the tank, then order it “salt-and-pepper” style. Big round tables aren’t designed to be communal, but end up as such when multiple small parties are combined. Most of the clientele are Chinese locals. If it doesn’t violate your ethics, R&G Lounge is a good place to try shark’s fin soup.