I worked on an app that competed with a Microsoft app. Our app was actually winning in the marketplace. One year they release a new version of their app with some really cool features at the same time as the latest Windows release. Those features were based on some new APIs released with that version of Windows. Just gave their app a year leap.
Another evil practice was forcing PC makers to pay for a Windows license for each computer sold irrespective of whether the computer shipped with Windows.
Microsoft was pretty evil.