I love the authenticity of a farmer's market. I love being able to smell the ripe peaches and herbs and coming into contact with fresh and organic produce. It's great to talk to the vendors (sometimes farmers) about their produce or product. Even if you're not looking to buy anything there's something for everyone, plus it's always fun to look around.
From freshly baked goods (gluten-free, vegan, you name it), fruit juices, weird plants and camera crew this farmer's market is by far my favorite. It's even been my savior at times when I found myself close to hangry.
If you plan on visiting, Mondays, Fridays and Saturdays have the best turn out with a majority of all the vendors being there.
For more information about Union Square's Greenmarket, check out their site here.