system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can I stream live TV, Netflix and even porn in crystal clear HD, but YouTube buffers and lags like no tomorrow?

It's infuriating.
gpt
YouTube has long been notorious for having lousy servers. To an extent, it's probably "you get what you pay for". Netflix has a vested interest in insuring a feed that isn't laggy because you're paying them every month for the service. But YouTube is free, so Google isn't going to turn the world upside down to make sure you get a great feed 100% of the time. 

Indeed, you'll often find that when YouTube feeds you an ad before the video, it comes through just fine, then the video itself will look like shit, or sometimes end up not even loading at all. That's because someone's paying for those ads, so they're sent from a completely different set of servers, and funny enough, they NEVER seem to have any problems with those.