I don’t know this man, so i make no judgements. Perhaps he is alone, as in truly alone and is at the bar to drown his sorrows. Perhaps he is waiting for someone, that person is late, his beer is getting warm, and his arms are crossed in impatience. Perhaps he is just lost in his own thoughts, whatever they may be, stroking his glass of beer and noticed his reflection in the mirror. Perhaps he wasn’t looking at the mirror at all, but at one of the many bottles of liquor lined up underneath it.
Only he knows, all we can do is stare at the photograph and ask (and guess).