Nothing wrong with that! The main thing that keeps me on Pale Moon (beside the fact that it just works--and works great!) is that by way of extended support for legacy add-ons I still have access to a very neat XUL extension, QuickJava. This is the most useful of all XUL addons as it offers immediate/convenient toggling for JavaScript, Java, Flash, SilverLight, cookies, images, animated images, and CSS. Of course, these things can all be toggled in about:config, but I've never been comfortable with messing around with it. QJ is safer, and FAR more convenient. Sadly, there does not yet exist a suitable alternative for Firefox Quantum; if QJ ever gets ported, I'll have my first good reason to upgrade. Since Pale Moon still supports XP, and since XP on its own is much easier to set up than newer versions in my experiences, I keep it going! There is nothing compelling to me about the computing of today, from what I've seen. Never before has the phrase "change for the sake of change is not progress" rang truer than it does today. Modern programs/OSes (and modern versions of longtime programs/OSes) don't offer major improvements compared to their predecessors in terms of what you can accomplish with them. The only major difference (not improvement) is that they have more bells/whistles, in most cases providing nice decoration but failing in all but a few instances to add worthwhile features. They are also much more bloated in terms of size and require newer hardware (multi-core processors, 2/3GB+ of RAM, a high-end graphics card, etc) in order to run with acceptable speed/performance.
XP was made at a time when the requirements were lower, and aimed to offer power/flexibility for both business & personal/recreational use while still retaining compatibility with relatively ancient hardware (Pentium I/Pro/MMX being the minimum you can run XP on). This philosophy was abandoned starting with Vista/7, which struggle to function well on anything older than a Pentium III (and even THAT is pushing it), and software is following the same trend today: add unnecessary bloat/bells/whistles and bog down the speed enough that it forces the end user to invest in modern hardware (even if they may not necessarily have the money to afford it, and/or even if they're fully happy with what they're using). Another trend in modern software/OSes is to remove useful features (or at least hide them or make things more difficult to adjust). XP was the last version that easily allowed you to change your startup/shutdown sounds; starting with Vista the startup sound is kept in a bizarre proprietary format which cannot easily be modified without the use of a third-party program. For some this may not be important, but for me it is essential to have easy access to that feature just in case I want to hear something different when I turn the computer on and/or when I shut it down. Firefox's old XUL/XPCOM system was far more powerful and flexible than what Mozilla introduced with the 'Quantum' series. At the very least, they could have at least been considerate enough to add graceful fallback for these older extensions--a compatibility layer that would allow them to at least perform their basic functions (even if certain features wouldn't work properly, at least without modifications). But no...they stripped it ALL out, and now those old essentials are all but useless.
I understand that 'forced obsolescence' has always been a thing in the world of technology, that anything technological is only supported for a finite time and eventually gets discontinued. But these newer operating systems, and newer programs/newer versions of longtime veteran programs, are woefully ill-equipped compared to their predecessors when it comes to offering a smooth experience and/or being able to function well on virtually any hardware one cares to use. Now I'm not saying modern programs should target a 386 or 486; those are way too old & slow now. But even a Pentium III, with enough RAM, is still a heavyweight (or at least a middleweight) for today's tasks; even on a dual 1.4GHz Tualatin setup with 3-4GB of RAM and an SSD the latest versions of programs targeting SSE1/older run rather slow. There is NO reason why any OS, or any program, should not be able to run well on hardware like the above-described. Nothing is getting properly optimized for older hardware, save for a few exceptions, and while some of it can be chalked up to the incompetence of younger programmers in other cases this is intentional on the part of the developers, as a way to force people into upgrading to newer hardware. It is sad when a company is so devoid of compelling reasons for people to use new hardware, or newer versions of software, that they all but trap the users in a corner and MAKE them upgrade. That is a despicable business model, as the end goal is not the users' happiness but the company turning a profit. If an OS or a program is genuinely good, it should be able to achieve success strictly on its own merits, not by people being left with no option but to switch. That's how XP got dethroned as Microsoft's most popular operating system; not by Vista, 7, 8, 8.1, and 10 being genuinely superior to the old warhorse in the areas that matter most but because of planned obsolescence. It is also why Firefox Quantum overtook older versions--planned obsolescence (support being ended for OSes, features being taken out).