There was a wave of dentistry that used nitrous oxide. It petered out and then there was another one in the 1970s. The first one gave us the titles, I think.

I've often wondered: if Mary Poppins developed the expressed hubris to fit the Extraordinariness with which she was regarded, would the world she was friends with collapse? She has significant sartorial vanity, but she refuses to say "I did this."