> Maybe it upset you
I only said that because I didn't want my comment to come off as goading you into upgrading for the sake of it. I know a bunch of people using older versions of software and are very happy doing so. I was just pointing out a few things off the top of my head I've liked in newer versions in case you weren't familiar with them. Many of them were better integrations with things like iPhone and AppleTV, which might not apply to many people.
a few sporadic replies:
* Notifications: very few things apps supported growl and I like the integrated implementation better. Growl also started charging money, which is fine, but yet another thing to juggle licensing and that friction drove me away.
* multi-monitor: People complained about multi-monitor handling in OSX /a lot/ until the last few years. I haven't heard of any problems recently (maybe I've missed it). I don't deal with it that much, but I still have problems with Windows and Linux...dialog boxes popping up straddling two windows, for example.
* Native fullscreen: Fullscreen API was added in 10.7, then changed in 10.8 and again in 10.9. It sounds like because of a limitation at the time of the initial implementation it was integrated with Spaces which blanked out the second monitor. If I remember, there was an option to have each screen use separate "Spaces" to avoid this and in recent version it works out of the box. I think some apps like VLC or iTerm still use their own fullscreen implementation--but now all apps can be fullscreened without developer intervention. I just pointed it out because as it exists today, it's a new feature like to use.
* Compressed memory: compresses RAM when it can. Improves performance on lower-end hardware. I don't know about this specifically, but I've seen this kind of thing actually increase performance where i/o is more of a bottleneck than compressing.
* Spotlight: I rarely use it for file search (that in itself hasn't changed since SL), but I use it all the time as an app launcher and calculator.
My beef with Windows crapware was always applications that run on boot, or something that would throw pop up notices after they expire in 30 days. OSX has always had a bunch of application I never use: Automator, Calculator, Chess, Dictionary... just hide them, delete them, or ignore them.
The reason your new applications require new versions of the OS is because the frameworks got better. If new versions of the OS were just adding new applications you don't use, then people would still write their applications with the older, better APIs.