Firefox still suffers from a lot of minor quality of life issues compared to other browsers, I don't know if it's neglect or weird internal politics but they add up to making firefox less attractive than the competition.

A few off the top of my head:

* Firefox doesn't respect Windows 10's titlebar accent colors

* No option to set a default zoom level for web pages

* Firefox for android ignores intent filters

The first two have addon or userstyle workarounds which makes it even more baffling that they have remain unsolved issues for years.