Mozilla 2017: Competing with Chrome is hard. What if we break all existing extensions and never let people replace them all?

This is the one that broke my back. Understandable that XPCOM extensions had to go, but leaving nothing to replace them, and then going on to push their trash UI redesigns without giving us any recourse to change them back - that was just unforgivable.

Then again, that was still well before they started pushing spyware in their own browser, so in retrospect, those were very quaint times!