That's the point, you don't choose when to first come across something you haven't heard of before. You don't wake up one morning and say "I guess I'll go to the library and get a book about Javascript" because you dreamed about it.

There are a million ways to display and to drill down into options that would make the FF options less cluttered, more logical, while having even more options than it does. There are ways to inform users pretty much exhaustively via built-in tooltips and documentation -- all of this has been working great in the 90s and got better since then. Icon > Title/Tooltip > Short Description > Verbose Description, so you learn everything you "stumble over" once when you need it, and from then on just use it, with the option to refresh your knowledge anytime.

Just compare about:config in Opera and Firefox, and simply accept we're dealing with different levels of skill and taste here, not just different choices.