I’ve had the typical disasters with partition tables and boot loader mixups, but the one I keep coming back to is updating my Nvidia drivers too eagerly. Whether something gets messed up with an external monitor, or the laptop starts resisting switching away from the integrated GPU, or an electron app I use regularly that makes heavy use of 3D acceleration breaks, or I just need to bump the driver version in a reproducible system state record… it’s just bad news.
I barely played the AC games as they came out, but recently decided to give Unity a try. It’s a really stunning presentation much of the time, but I find myself setting the game aside quite regularly as the quests / missions can be rather dull. I should perhaps try to do better at picking what to do in the game, as the immersion can be compelling.