For reasons that will become clear, I can’t structure this article as a “falsehoods programmers believe” article, much as that would add to the effect.
There are plenty of such articles in the world, so turn to your favourite search engine, type in “falsehoods programmers believe”, and orient yourself to this concept. You’ll see plenty of articles that list statements that challenge assumptions about a particular problem domain. Some of them list counterexamples, and a subset of those give suggestions of ways to account for the counterexamples.
As the sort of programmer who writes falsehoods programmers believe articles, my belief is that interesting challenges to my beliefs will trigger some curiosity, and lead me to research the counterexamples and solutions. Or at least, to file away the fact that counterexamples exist until I need it, or am otherwise more motivated to learn about it.