Boiling frogs and PC performance
If you'd asked me a week ago, I would have confidently asserted that the performance of my old home machine was pretty much fine (with a few narrow exceptions); certainly no longer top of the line, but still mostly more than adequate in general. Sure it was five years old but I'd gotten reasonably good components five years ago, I don't do many things that are performance demanding, and anyways I've long heard (and agreed) how both performance demands and system performance have leveled off.
I was wrong. There's no other way to put it. Using my new machine has been a revelation in how much my old machine had quietly been slow. Even for programs that I knew were compute-heavy, the change has been dramatic. And other programs have kept surprising me when they're noticeably nicer and smoother on the new machine.
(My favorite example of improvement is that my photo processing program has not merely gotten faster at doing the same things I was doing before, it has turned into an interactive editor where I can drag adjustment sliders and see the results instantly.)
When I look back at this, I think that happened is that I was being the computing equivalent of a frog being boiled. Sure, my machine had performed well five years ago, with the programs of five years ago. But over the past five years, both programs and what we do have slowly become more demanding, bit by bit. As things got more demanding my machine's effective performance slowly degraded, but because this was a slow and progressive change I didn't consciously notice anything. Things were just a little bit slower than they were last month, never suddenly a lot slower, and soon enough it became the new normal that I expected and was used to.
In short, I had gotten accustomed to having a genuinely slow machine. And because it had happened gradually I didn't realize that it was possible to have a qualitatively different and better experience with a modern fast machine; I expected only moderate improvements from the upgrade, not an eye-opening sea change.
(Okay, there were a few things that I was hoping would speed up visibly, but that was because they were broken to start with and I would be throwing huge amounts of memory and CPU at them in the hopes of papering over the issue.)
(In retrospect, I perhaps should have noticed that there were an increasing number of things that I wasn't able to do. I've never been able to view Flash-based video in HD, for example, and I knew that was a CPU issue, but I sort of wrote it off as 'oh, Flash on Linux is just handicapped in general'.)