Back when iOS and iPad were eating Microsoft's lunch in mobile, Microsoft freaked out and released Windows 8 with that new tiles UI framework ("desktop and tablet are going to converge so we need to dumb down the interface") and the Windows Store that was supposed to be their response to the App Store. Microsoft wanted all future Windows software to be released through the App Store. Of course, this was an existential threat to Valve/Steam, so Valve vociferously pushed back.

The Windows Store and its apps were so bad that Microsoft eventually scaled back their ambitions, but Valve has not forgotten.