London, UK. As conwy mentioned, it's not luxurious but it is doable. It helps I'm not really all that social, I don't like crowds, nor wasting money. Don't get me wrong I've done my fair share of both and I still go out once a month, but I have a limit on what I will spend because trust me it is far to easy to go into central London and end up spending a ridiculous amount of money.
Most of my socialising in the past 6 months has been staying in or going to a friends house. A couple times a week, we will cook each other dinner, maybe have a beer and generally just relax. It's basically a "habit" now and 1 that I really quite enjoy, all of our cooking levels have improved and we experiment a lot both with simple dishes and different styles. There's only been 1 occasion when we've all said no and thrown it out, admittedly my fault. I seriously misjudged some chillies, lol.
Also, as cowy said the bay area is 1 of the more expensive places to live. You make a choice to live there, I know it might not be that simple, but it is a choice none the less.
If travellings your thing, on a 12k/y budget you could do most of Europe, Asia and probably more. I did the calculations once when considering travelling for a couple years, of course your not going to be staying at 5* hotels in a gated community, fine dining, but that imho isn't travelling.