I find backronyms as false etymologies fascinating; people seem to desire more interesting explanations for the origins of words than the more likely explanation. “Phat” is sometimes explained as “pretty hot and tempting”, but the fact is it’s just a deliberate misspelling of “fat”, nothing too interesting about that.
But I never knew that “SOS” was not an acronym; I always thought it was. Learn something every day. :)
My favorite backronym is probably the D.E.N.N.I.S. system for seducing women and earning their “undying love”, created by Dennis Reynolds on It’s Always Sunny in Philadelphia. It stands for Demonstrate value, Engage physically, Nurture dependence, Neglect emotionally, Inspire hope, Separate entirely.