(FWIW, and having done it a few times, I'm inclined to think that falling over while standing still does not quite meet the definition of "stupid". It's usually a physiological/neurological phenomenon, rather than a result of, say, knuckleheadedness or unthinkingness, like
driving too fast on slushy road. Embarrassing, maybe, but only around wrong company. Like anything one does because of actual lack of intellectual capacity or because of scarcity of good information. Of course, if there is some basic technique that would prevent it from happening, and we forget to or refuse to deploy it, that would be different.)