I'm constantly perturbed and interrupted when some app window just 'hangs' for a few seconds (some garbage collection going on, probably?). I can't pinpoint any one thing, just... everything seems relatively slow in 2022 compared to, even 10 years ago, and certainly 20. Applications weren't always phoning home to check things during bootup, which I suspect happens a lot now. Our computers are dozens of times faster than in the 90s, and, computationally, some things get done much faster, but others - around UI, it seems - apparently regress.