A lot of times these updates are meh. It's why I personally don't care that much and spend a lot of time going "where's my update??? Where's my update!!" instead of just enjoying a good device .
Most times thus far, a number has changed, some interface elements switched around and maybe some new software function added. If I'm honest, it's rarely anything more exciting than a theme change and downloading some new apps giving me near the same satisfaction level. That is to say... meh.
If it unlocks some hardware feature of my phone I didn't have before, speeds up radically, improves function noticeably, gives me access to apps that would otherwise be incompatible etc... then I dig an OS update. But it's rarely that. And sometimes I've seen people fume over it being LESS than any of the above.
(Can't recall an update personally that's actually slowed my devices, but that sure would make me question the point of an update obsession if I had one ).