Well, hurleygirl, if I have to say "on your left" 5000 times during a ride to be considerate to others, and avoid a possibly unpleasant incident, so be it!! Common courtesy is not always convenient.

By the way, there were plenty of people on that ride who were courteous and communicated with those ahead of them...but it only takes one who is tired of saying "car back" or "on your left" to cause a major accident.