I open the preferences window. Well, not quite. Instead of a preferences window like every other application I've ever used, it's some sort of webpage which opens in a new tab in the same window as the webpage I'm browsing. The controls are all completely custom, and the layout looks nothing like any preferences window I've seen since Netscape.

Also, the Firefox UI doesn't use the same language as the rest of the OS (which is English), or even the webpage content displayed by Firefox (also English). It's all displayed in the language I tried to learn last year, for some reason.

In the search box at top, typing "language" finds nothing, and typing the word for language in the language I'm seeing shows a fancy control with "English (United States)" at the top. There's nothing I see which would indicate why the UI is not English. I google for "how to change firefox ui language", and all the pages I find say to set it here, and restart.

Thus ends another adventure in attempting to use Firefox, and it ends the same way all my adventures do: nothing is standard, everything is custom, and so it doesn't work right. This time, I didn't even get far enough along to complain that all the keyboard shortcuts are broken.

Dear Mozilla: for Firefox to win me back, it has to be a good web browser. Stop trying to be an operating system. I already have one of those. "Look/act like every other application" is the correct answer in every case.