One that got worse and then better again at least in my experience is boot up time. Old computers running MS-DOS I remember booting up very quickly (unless you waited for the full memory self test), then for quite a long time it took forever to get into Windows no matter what you did to try to speed it up. More recently things start up pretty quickly again; I think it's mainly hardware (solid-state disks being the ma…
Likewise, my Windows machine hibernates so fast that boot time feels like I'm just waking it up from sleep.
Thanks to the advent of SSDs, applications are also quite peppy to startup. Music, movies, pictures, all so fast to use.