Not 99%. Windows has many usability issues. I’d vote for “dont steal focus and stick windows in front of where I’m typing” and “don’t move things just as I go to click on them” for a start, and also “don’t somehow take an hour to delete 50 files.”
Deleting files was an amazing one already. Then I recently discovered the joy of deleting 30k emails from Outlook… T-T

I literally cannot understand how Outlook is so awful and unpleasant to use. Constant pauses, regular freezes and a search that will show a document I sent to myself five years ago regardless of search terms but won’t surface the perfect match I received yesterday, in the world’s most prominent email client.

The only worse software I have to interact with on a daily basis is Adobe’s PDF reader, which gives me five popups within one minute of opening it.

I typically use my browser for PDFs. Firefox actually has some basic PDF edit functionality now.
But better disable javascript use for pdfjs.

I literally cannot understand how Outlook is so awful and unpleasant to use.

Years of hü and hott between different teams, with different goals, not knowing what the other does.