One thing I like about the farmer's market is that you can sample most of the produce before you buy it. It's all local stuff, and probably picked only a few hours before you taste it. I'm a big fan of "try before you buy."
The other thing I like is the produce itself. It's all delicious, because it's all in season, and all picked only once it's ripe. They have everything -- lettuce for my BLTs, fresh eggs, blueberries, cheese, bread, pretty much anything that is currently ripe in northern California is laid out on tables, ready to be chosen, taken home, and eaten. The white peaches are amazing, and somehow impossibly sweeter than canned peaches. The strawberries are enticingly red and shiny.
But two things in particular make me love the Mountain View farmer's market more than any old market or supermarket.
Pluots and heirloom tomatoes. Sun-ripened, juicy, and delicious enough to warrant less sleep on Sunday morning.
Sorry, Zurich, you may have my favorite airport, excellent lake access, and the most efficient public transportation system, but you never gave me pluots. New York, I miss your convenient delivery services and infinite possibilities, but heirloom tomatoes never appeared on my doorstep or at a museum or bar while I was there. Do you have any idea what you're missing out on? Maybe it's best if you don't, because it would be pretty hard to know about such things and live without them.