According to the Script

Encounter with a friend, acquaintance or just someone in a bar is merely a pretext to display your theory of what you are. Absorbed in your own performance you applaud or criticise, and only to watch your reflection do you look into his eyes. Or, if a contrast’s noticed, it’s to serve as a backcloth useful for the setting and to show your costume off. He thought you concentrating when you were running through your lines rehearsing gestures while waiting for your cue. Still soliloquising you said goodbye, went on, and never knew that the stranger, the other had been speaking to you.