you obviously haven't used win 7 before SP1. I used win 7 from the beta to the latest versions and I can assure you that after thousands of installs it had a ton of bugs, blue screens galore. before the 8.1 version, win 8 also had some big problems. But since win 10 builds on top of win 8.1 major bugs are rare. I'm not saying that they don't exist, but it's clearly a much more stable OS than 7 or 8. It's also much easier to fix win 10 than win 7.