Well, the notion of "performance" is an interesting one. Several years ago there were animated discussions on The Session website about whether players (like me) in pub sessions were playing exclusively for each other or whether they were performing for the punters in the bar. Well I always concluded that what we were doing was never a performance (even if we were getting paid with free beer). The people in the pub were not part of the transaction in any real way. If they constituted any kind of "audience" at all, it was of the loosest possible kind. Us musicians were fully committed to each other in that there had been no pre-planning, no rehearsal and no arrangements, so we were always on our mettle. The "audience" were free to chatter, shout, ignore us, talk loudly over us, clink their glasses, walk around, go for a piss or have a fight. If we added to the ambience, and clearly the landlord thought we did, that was a great bonus for all concerned, but that was never the aim. The word symbiosis comes to mind. Is singing any different? Well who are you singing for, or to? You are using the language in singing that everyone uses every day. I'd find it odd if people I encountered in any of my ordinary daily transactions kept their eyes shut when they were talking to me. I wouldn't be offended but I'd regard it as their problem. Just sayin'.