Been to SFO airport so many times. The most important thing to remember is that is it a very busy international airport, but due to its location it has a very limited number of landing/takeoff runways. So, with bad weather expect major delays. Plan ahead and realize if you are catching a connection from SFO, it could be severely delayed, causing you to miss your next flight. I always give myself 2 hours at minimum between connections. If there are no problems, then I have time to hit the bar for a quick refreshing-adult-beverage.