For one, MS doesn't test updates anymore. You may get something pleasant like losing the ability to print, or having all your network cards vanish.
I had a stack of Mac Minis years ago that I used for various things. One update bricked half of them. I was able to fix them easily, but it should not have happened at all. I installed from scratch on one of them, and an update bricked it. I did nothing to the computer in between the fresh install and pressing the update button. Neat.
The bottom line is Apple and MS have long ago stopped caring about the quality of their products.