I subscribe to a lot of pointless YouTube stuff, lets be honest, who doesn't.
However, there has increasingly been a movement towards the production of high quality, educational channels, with the intent of providing free learning to the masses. I am totally on board for that. So without further ado (I just learned a grammar lesson on that one) here are some YouTube Channels you should be watching, they will definitely not be a waste of your time.
Hank Green's SciShow
John and Hank's Crash Courses (the Biology one was amazing, Chemistry looks pretty good so far)
The Brain Scoop with Emily Graslie (sometimes graphic...dead animal parts)
DNews (D is for discovery)
The wealth of information, easily accessible online, for free is one of the true wonders of the internet. YouTube, TED talks, and more, wasting time on the internet has never been so productive. What YouTube Channels spark your interest most?