It may seem like a small thing, but when you have literal decades of muscle memory working against you, it's not that small.

What messes me up when I'm working on a linux machine is not being able to do things like copy/paste text from the terminal with a hotkey combo because there is no CMD-C, and CTRL-C already has a job other than copying.

IMO apple really messed up by putting the FN key in the bottom left corner of the keyboard instead of CTRL. Those keys get swapped on every Mac I buy.

I agree on the Fn key positioning... I hate it in the corner and tend to zoom in when considering laptops for anyone just in case. I've also had weird arrow keys on the right side in a laptop keyboard where I'd hit the up arrow instead of the right shift a lot in practice... really messed up test area input.

It's the same thing when switching from a Nintendo to a Western game where the cancel/confirm buttons on the gamepads are swapped.

But in the end the biggest thing to remember is in MacOS a window is not the application. In Windows or in many Linux desktop apps, when you close the last or root window you've exited the application. This isn't true in MacOS, applications can continue running even if they don't currently display any windows. That's why there's the dot at the bottom under the launcher and why you can alt+tab to them still. If you alt+tab to an app without a window the menu bar changes to that app's menu bar.

I remember back to my elementary school computer lab with the teacher reminding me "be sure to actually quit the application in the menu bar before going to the next lesson, do not just close" especially due to the memory limitations at the time.

I've found once I really got that model of how applications really work in MacOS it made a good bit more sense why the behaviors are the way they are.