"It happens in an awkward and possibly crowded and noisy place - near public transportation, shops or other distractions...there is often no place to sit and standing around can make you feel conspicuous. We do not know who the performer is or if she is any good. This feeds into the anxiety that many people have about their own perceived lack of taste or knowledge. They do not want to be seen by others to be over-enthusiastic about a mediocre performer or under-appreciative of a good one. It is safer not to listen and thus not to betray any opinion at all...And even if we do stop to listen and enjoy the experience, what would be an appropriate way to show appreciation? Clap? Say "thank you"? Make a contribution? ...If you give too little you look stingy; if you give too much you look like an easy mark. All of this makes for a very awkward situation and it is much easier not to stop in the first place. Better to get on with your business."

Why music moves us by Jeanette Bicknell, 2009. ISBN 9780230209893.