Laura Rose’s Answer
It is VERY hard to open a restaurant and perhaps even harder to run one. You should spend a LOT of time in a restaurant before deciding to open one. The first 3-5 years it's open you have to be there everyday open-close. It is exhausting and draining.
That being said, it's very rewarding to serve people beautiful food in an atmosphere where they feel comfortable.
San Francisco in particular is especially dense and filled with many good restaurants which means it's harder to stand out and survive.
Good luck, whatever you choose but I would be VERY sure before making any final decisions on starting a restaurant!