I changed to Chrome from Firefox a year or so ago primarily for performance reasons even though it felt like a major sacrifice swapping to the 'minimalist' type UI of Chrome though it wasn't too tough to mod it to an approximation of earlier versions of Firefox. Recently Chrome has swapped to a policy of automatically disabling all extensions that don't come from their store (even after users jump through all the hoops required to install/develop non-store extensions) with no way to disable said "feature" so it was time to drop them as I prefer freedom in browsers above all. Lo and behold I come back to firefox and I'm still experience a bit worse performance, but on top of it the UI is now clearly heavily influenced by exactly what I was trying to avoid with Chrome, with no straight forward means of reverting to previous Firefox UIs. Why not simply change the UI using a sort of XML or other setting file? It'd be trivial to be backwards compatible (so long as new versions don't remove any functionality) and allow users to easily choose exactly how they want their experience to be. Now I'm sure the answer is something like "We did user research and spent a millenia researching the new UI and even had Mohammed Ganesha Jesus himself come tell us exactly what users want so we decided to force it on everybody!" but honestly I don't really care. I like to stick to a simple dictum of "If it's not broken, don't fix it." It wasn't broken for me, so I have no interest in the fixes. I'm always enthusiastic about back end fixes, but if I'm happy with the front-end why force me to change it?