What bar or club in DC has the friendliest vibe?

I’m looking for a bar or club in DC where I’m most likely to meet friendly young people (20’s and 30’s) like myself. I’m sick of places where everyone is either dancing to music so loud that you can’t have a conversation, or where people are cliquey and groups stay at their little booths, tables, or standing circles. I’m ready to mix and mingle…but where do I do it?