[rferr48792]

Learning to sail is like learning most things. Sure you can probably pick it up on your own but it will take you twice as long if not longer and you'll probably develop a lot of bad habits.
Learning to Sail at a sailing school will give you the basic sailing fundamentals that you need to know to understand how to operate a sailboat on San Francisco Bay. Like anything you learn you need to practice to refine your skills and develop your self confidence. The first year you should sail as much as you can whether it's with friends, chartering, joining a club, racing, cruising whatever. It's the time on the water that will make you a better sailor. Racing is also a great way to improve your understanding of making a sailboat perform well. Most of the sailing schools on the Bay teach similar standards. Sailing fundamentals are sailing fundamentals and no sailing school has anything overly special about what's in their courses that differ much.
So long as the instructors are quality people who have experience, patience and make learning to sail safe and fun you'll have a great time. If you live in the south bay and you want to learn to sail the bay, Spinnaker Sailing in Redwood City is a fine choice. They have been teaching for over 30 years and have some great instructors. It's the same as when you were in grade school, high school or College the Instructor can make all the difference. If you want to learn to sail dinghy's then Shoreline Aquatic Center in Mountain View is one of the few places you can learn to sail a dinghy.
Don't listen to someone who tells you to just go out there and learn on your own. A bad experience can cost you severely. The Bay is not a place to play around in without knowing what you're doing.