This is not specific to Windows, but reasons not to upgrade a system: - New bugs. Most recently, my iOS 15 made my bluetooth headset twitchy in new subtle ways

This is not specific to Windows, but reasons not to upgrade a system: - New bugs. Most recently, my iOS 15 made my bluetooth headset twitchy in new subtle ways. Now it will unprovokedly switch from headphones to speakers without warning. If I pause whatever I'm playing and press play, it will go back. This is very unfortunate. Thank you, upgrade. - Arbitrary UI "improvements" break workflows and simply change the look/behavior of things I didn't ask for. Menu layout changes means you no longer find things in the places they used to be; maybe the new place is better, but it places a burden on constantly having to re-learn menus. Microsoft Office, in my experience, has offended the most here. Compare this to UNIX command-line tools where parameters have not changed in decades upon decades. > To stay still is to accept ever increasing vulnerability That's what security updates are for. If software vendors would differentiate between - security updates - deprecating old APIs/libraries - adding new features then we might have more software that Just Works.