I was tired. I had been traveling. Perhaps I was dehydrated or congested, or maybe the altitude was getting to me. But as I walked down the hallway of the Park City hotel, the floor tilted and threw me against the wall. I stood there for a few minutes, hoping the floor would return to its usual flat and stable position. It was a bout of vertigo, brought on by who knows what. My balance returned as the morning went on and that disconcerting feeling hasn’t returned since, but I vividly remember the disorienting walk down that hotel hallway.