One of the biggest issues with Firefox for me has been the U2F support - because they came so late to that party and so many of the web sites that do support U2

One of the biggest issues with Firefox for me has been the U2F support - because they came so late to that party and so many of the web sites that do support U2F gate it by user agent instead of feature detection, because Firefox was so slow on the uptake, they made a lot of problems for everyone and set back one of the better security standards. I also have a big issue with their handling of webm/webp. There was one single guy at Mozilla killing that for years - may still be - despite heavy demand for support. Both were really disheartening because it showed that Mozilla had lost its fight and had become so complacent that it didn’t even feel the need to match its competitors much less try to lead. On the flip side Chrome has now become so comfortable with their position that their users are more of an annoyance, which lets them do very unpopular things like pinching off all of the ad blockers. This is where Mozilla could make a comeback because I think a lot of people (myself included) would take another look at Firefox if that is what it took to keep ublock and ghostery functioning.