One person goes along a wall listening and listening.
Others come along and ask him what he is doing.
He says dramatically, “Listen,” and the others do.
One of them says, “I don’t hear anything”, in a disgusted voice.
“LISTEN”, he says more dramatically and they listen some more.
Again someone says, “I don’t hear anything.”
The original listener says, “You know,” with a faraway look, “it’s been like that all day.”