It starts innocently enough. You crack open a jar of something from the pantry. You use a bit of it. You go to put it back on the shelf when you ask, "Should I put this in the refrigerator?" You do the bottle roll in your hand to see those prophetic words "Refrigerate After Opening". You look on the label. Then the cap. The the bottom. It doesn't say it. So you put it back on the shelf. But, in the back of your mind you're wondering, "Why wouldn't it need refrigerating? What if I missed it? What if they're wrong?!" So, you go grab it and put it in the fridge.
After a while you may have the opposite question. Why does this need refrigerating? Nothing in the universe can live in a bottle of soy sauce due to the salt. So, why does it tell you to refrigerate it? It can't possibly go bad! You've kept it on your pantry shelf for years and never gotten sick. Are you just lucky?