It's Not Just You, YouTube Looks Like Crap Right Now
Usually you can blame a low-quality video stream on a bandwidth slowdown or a poor internet connection—sites like YouTube will adjust a video's resolution accordingly, so instead of a crisp HD or 4K stream, you end up with a blurry, pixelated mess. You can manually adjust the resolution to make it look better, but you'll probably run into buffering issues, since your internet can't keep up.
Recently, however, something else is happening to cause YouTube video quality to tank. Users are reporting that when they start a video—whether it be a YouTube Short or a standard clip—the stream will load in very poor quality, anything from 360p all the way down to 144p. While some are able to manually adjust the stream to a higher resolution (like 1080p), others find that doing so just results in endless buffering. For many right now, it's blurry videos or nothing. This isn't isolated to a specific browser or platform, either: Users on iOS, desktop, and smart TVs have all reported experiencing the same strange quality issues.
It's possible that a fraction of these users have slow internet connections, but it's virtually impossible to conclude that all of them do. In fact, there are many complaints that, despite a fast connection that powers other internet activities without issue, YouTube insists on playing videos back at an unwatchable resolution.
Luckily, YouTube itself is very much aware of what's happening. In a post to its support page published on Wednesday, the company identified the problem (144p or 360p defaults that buffer endlessly when changed), specified that it is indeed affecting iOS, desktop, and smart TVs, and shared that it is working on a solution.
You'll notice that there's one platform that isn't affected by these issues: Android. As of this writing, it does seem that Android phones and tablets are unaffected by these recent quality issues. It's not clear why, beyond the fact that YouTube and Android are both operated by the same company (Google), which doesn't really explain what's going on here.
Is there any way to fix the YouTube streaming quality problem?
At this time, there really isn't much you can do but wait for YouTube to fix the problem. You can, of course, attempt to change a video's resolution manually from the settings gear under Quality, but you may find you're stuck with blurry playback, or run into the endless buffering issue.
It seems silly, but at the moment, the only real workaround is to watch YouTube on Android if possible. If you have an Android phone or tablet, use that for your YouTube needs over an iPhone, iPad, desktop computer, or smart TV. The rest of us will have to hope YouTube issues a quick fix.