An uncontroversial thing the Americans got right

Diarrhea.
I have just learned how to spell it properly. The British spelling of diarrhoeia is illogical. I had to look the damned spelling up.
Thus I have derived a little more knowledge thanks to some vintage US advertising.

I'm going to need a good few hours to plough through some other examples of Giant magazine's "50 Greatest Commercials of the ’80s", but at some point I will, because there is something fascinating about the naked commercialism of US ads from this era.