Meatloaf.
A simple enough dish, right?
At least to any American mind, which likely imagined something like this:

It’s just a loaf of meat – how could that possibly be misconstrued?
Until you order a meatloaf in Europe and you get this:

The most important thing you can know is that you know nothing.
There’s always the possibility – regardless of your confidence level – that an alternative reality exists outside your personal little experience bubble.
It may be worth a peek outside that bubble every once in a while to test some of your assumptions – in particular the ones in which you have the highest confidence.
Some instances are harmless.
This “new” form of meatloaf that I accidentally discovered a few years ago was actually pretty tasty, but even if the outcome had been different, no major harm done. A few swigs of beer to cleanse the palette and a couple euros to pay for the meal, and it would have all been forgotten.
Other examples have greater impact.