There are many distractions. The television is on without sound. There's a record on the stereo. The phone rings. The conversation at the next table takes an interesting turn.
People formulate answers instead of concentrating on the questions.
They remember jokes. When it comes to musical conversation, a.k.a. collective improvisation, many musicians concentrate on their ego and their technique and make sure they are following the rules before attempting to converse. They show off, communicate to the audience more than to each other. It ends up as a string of monologues, not a conversation. They require energy, concentration and spirituality.