Today I have had a very bad experience when I was traveling in the subway C line.
Suddently a "popular guitar player" appeared in the carriage and began to play his caribbean music (which I do not like). But the worst was that he connected his guitar to a loudspeaker, which was unbearable.
At the end of his performance I told him that this was an invasion to the personal room that one must respect. He was not outside, was inside the carriage.
To my surprise, several passenger gave him a tip. I am assuming that I am an enemy of the poor people that tries to have money with this almost useless activities,
I cannot imagine doing this in a London subway