Destiny 2 has seen a lot of bugs over the years. We've had balance-breaking bugs which let players delete bosses in seconds, heartbreaking bugs which made rare rewards that much rarer, and just plain annoying bugs which marred otherwise great activities. Still, those bugs were all fairly isolated, and they were fixed relatively quickly. They don't hold a candle to the worst bug in the game's history - a bug so common, so well-known, so teeth-grindingly, eye-twitchingly, mind-numbingly frustrating that it (somehow) couldn't be fixed for over a year.
Sometimes applying shaders doesn't work.
That might not sound like much, but trust me, this is the bug equivalent of Chinese water torture. More often than not, when you try to apply a shader - or use an ornament, hologram, or some consumables - the 'apply' progress will cut out right before it reaches the end. This usually only happens the first time you try to apply a shader, but closing the game or your menu can cause it to happen again. As a result, many players (myself included) have encountered this bug literally every time they've played Destiny 2 in the past year and change.
It'd be one thing if shaders and other inventory items just went on the fritz sometimes and you had to click 'apply' or 'use' a second time to get the progress bar going. But the fact that the progress bar just abruptly dies at freakin' 98% takes this bug to the next level. It's the difference between losing two socks and losing one sock. The latter is more annoying because you're more aware of it. If you lost both socks - i.e. you never gained any shader progress to begin with, and wow this metaphor's going off the rails fast - you could just give up and start over.
Oh, that same blog post also described one of the most promising loot grinds in Destiny's history. You know, as a prelude for this crucial fix.
