Depreciating old "features" like supporting legacy OS versions which is infuriating. Firefox is an inadequate substitute because too many sites only work in Chrome.
I blame lazy developers for this mess all around, which had caused a perfect storm of shit on the nouveau web.
As a person on a front-end development team that has a “Chrome = success” mandate, it’s not always our decision as to when something ships or for which platforms we are to target. We work on Chrome first and then hope for the time to get things to work elsewhere.