Brad Williams, the diminutive comedian with profound talent, has a particularly poignant ritual that he indulges in after a show. “I like to go sit onstage in the empty theater where I just performed and I just kinda … listen,” Williams said via phone interview from New York City. “It sounds quirky and it sounds stupid but you can kinda hear all the action that’s been there. You can picture all the people and you can just take in what you just did.”