I was unlucky enough to be grouped with a middle-aged American man whilst on London’s Jack the Ripper tour. We were just crossing a road when he turned to me and asked me why the traffic lights rattled. I told him it was to let blind people when they changed. He looked confused so I asked him what was up. He said “Well in my country, we don’t let the visibly challenged people behind the wheel of a hunk of metal!” and quickened his pace to get away from me, shaking his head.