You know how when you press the Windows key and are able to type into the searchbar? Prior to 10, this bar did an instant local-only search of your desktop applications and (if you enabled it) select cached documents. Imagine building up the muscle memory of using this to launch applications for a decade or two to the point where you don't even look at the screen anymore when launching apps. Now imagine that Windows 10 comes along and introduces a mandatory internet search that has to complete before it lets you see the local results that you were actually looking for.

Now imagine not being able to forget how snappy it used to be every single time you launch an application. Imagine the annoyance of being punished for a typo by having Edge open up a Bing search instead of the application you were trying to launch. Imagine not noticing the error and waiting 5 seconds for Bing to boot up, only to be confusedly greeted by a search you didn't ask for in a browser you wish you could uninstall. Imagine installing third-party applications to try and restore the old search experience only for it to get regularly broken by OS updates you cannot opt out of and are only sometimes notified of in advance (another "feature" that Windows 10 brought).

IMO Windows 7 was the last "pure" Windows before the power balance at Microsoft tipped in favor of the cloud & sales people.