Or, people thinking their male "needs a girlfriend". I knew someone like that. Hers lived in a 5 gallon together, for a year, then both died "the other from heartbreak"
I will admit though it bugged me when a store associate asked if I had FIVE tanks for my FIVE females, at least she was leaning towards an actual idealistic understanding of bettas. (Plus I had 5 quarantines, and some divided tanks if need be lol)