do people clap at the end of movies? It's not like the actors are there to hear you, or take a bow or anything.
do people feel the need to say things like "oh, that song is about..."? The whole point of music is that you get to interpret it for yourself.
do I always wonder when I'm singing along to music (with my headphones on) in my car, "This would sound pretty terrible if my phone accidentally dialed someone and they heard me singing this rocker song a capella right about now..."? Like that would ever really happen.