I wondered why a muscle spasm in my left shoulder started up 15 minutes ago. It presciently knew I would find this question. I've been pretty fortunate in SL that my grinds didn't really take that long. Certainly nowhere near the colossal pain I've seen others go through.
Rather than give you just the short answer and commiserate with your pain (which I will: Wyrmscale Greaves from the last boss in Old Hillsbrad, 24 runs), I'll begin deducing and analyzing the farming pain formula to which we submit our suffering. Others may be able to refine it better than I have.
(time spent) * (interest of endeavor) * (impact of gear) * (swag factor) = total farm pain index score
"Time spent" may be the number of dungeon runs we do, the hours BoE farming, number of chest or lockboxes opened, number of days checking an AH, etc.
"Interest of endeavor" is how engaging the content is. BoE farms take much longer than dungeons, but every kill in a BoE farm is a slot-machine chance for a win, whereas dungeons typically give you one slot machine attempt per run. We'll get greater returns on time invested by doing dungeons, but I find dungeon grinds harder than BoE farms because of all the dead time. Old Hillsbrad makes that especially painful with the enforced wait time between encounters.
"Impact of gear" describes how much better getting that piece of gear will make your character, compared to other available alternatives.
"Swag factor" acts as a positive benefit of the context in which you play.
This is why farming the Wyrmscale Greaves for my resto shaman sucked so much. It's the longest dungeon in TBC with no way to speed up the roleplaying parts, the encounters have no meaningful mechanics to them, I wanted the Greaves for arenas because the BoE legs I already had were BiS for battlegrounds, and all mail wearers get the Greaves so they have no swag factor. Grinding Old Hillsbrad is the most pain I encountered this expansion.
Contrast that with the (easily) 100+ hours (and counting) I spent BoE farming. Yes, that far outdoes the rest of my SL farming endeavors put together, but when I get a good drop? Daggone, it's BiS for someone, even if not for me. BoE farms build camaraderie with fellow BoE farmers. Every time someone in our group gets a good drop or (especially) a near miss, it ups the excitement a little. A stellar drop can buzz me for days, and brings more swag factor than any dungeon drop ever could.
My SL 49 took an hour a day, every day, for almost four months, for gear that quickly got nerfed. But that grind felt wholly different. I pushed a new frontier, and while 50s had already landed the SL rep gear (due to easier access to rep), nobody at 49 had made it to 4x exalted. The long time spent was nothing compared to the excitement of pushing a boundary of what was possible, the monumental impact of the gear, and the swag factor.
Building that 49 and farming BoEs with fellow 20s remain my best gear pursuit memories of Shadowlands. But my shoulder twitch still hasn't stopped, and Old Hillsbrad will continue to make people suffer.