I was on an airliner several years ago when the oxygen masks deployed. The interesting thing was that, despite all the times I had sat through (and paid attention to) the flight attendant safety briefings, neither I nor anyone else made any move to don an oxygen mask until some time had passed (it seemed like several minutes but I guess it was really much shorter time). Only after there was a garbled (totally unintelligible) announcement over the PA system did I reach up and "pull the mask toward me" as I had been instructed to do about a hundred times in the past. And most of the passengers around me didn't put their masks on until I did; everyone, it seemed, was waiting for somebody else to go first, or from some sort of "official" announcement that yes, this was the real thing and not some malfunction.

And the bizarre thing was that, even while I was thinking about whether or not to put the mask on, I knew that I was being silly and should just reach up and do it.