The happy hour at EZ5
(684 Commercial, off Kearny between Sacramento and Clay) has several big plusses. It runs from 4 (opening) to 8, an hour or two after most other happy hours have stopped. You can get a Sierra Nevada or glass of wine for only $3. It's right next to the Financial District, handy if you work there, but not actually in the FiDi, so you're already out of work zone. And it's a friendly place that draws a lively, happy crowd.
On the minus side, if you're hungry a helping of the free appetizers may be better than drinking on an empty stomach, but they're not a draw. The crowd is very young--when I took these photos, nobody looked much over 25--which could be a plus or minus depending on your demographic.