Mary laughs, at first assuming he was joking at thinking she was actually good - it was entirely too deeply embedded in her mind that people only put up with her because they thought she was cute, so complimenting her talent seemed a bit off. But she held the laugh to a friendly giggle while she looked at his face.
Is he for real?
"Uh, actually tending bar pays the bills. Did you really like it that much?" she replies after a moment of consideration. She neglects to mention she got interested in playing guitar again in the process of mourning the sudden departure of an ex who played the blues so very well. But she did have a different blood alcohol content now than then so that was on the side of maintaining compartmentalization. "I don't actually have a, uh, 'day job' technically? What do you do, while we're chatting about it?"
If anything was more embarrassing than being too drunk to remember the guy's best friend, it would be getting wasted and gushing about how she had found herself staring at the empty half of the bed and crying for months to the well-dressed guy who just offered her a drink for friendly conversation.