Having lived on the Peninsula for a year (+), I got very familiar with the bar scene. What they say is true, you'll find what bars you like the best and go there the most. One of the bars that I always wondered about was Sharkeez. It's a local spot, and always (and I mean always) busy. The first time I went to Sharkeez, I wasn't sure what to expect. Granted it was late on a Saturday night. However, I really liked it. It was a lot more casual than I had expected and the drinks were very reasonable.
One night, I grabbed my roommate and boyfriend (at the time, now he is the fiancé) and we headed over for happy hour. I was pleasantly surprised - not only were there really good deals (especially on beer), but while it was still crowded it wasn't like a Friday or Saturday night and we ended up with a seat on the patio (well if you want to call it a patio, it is more like a couple of outside booths). We had a great time and were able to hang out with a lot of people who lived near us (see we are making friends!).
I would recommend Sharkeez for a Happy Hour - it's really fun and the cost is very reasonable.