Almost every video starts out describing what docker is. It’s like you must know the relationship to virtual machines in order for docker to be useful. Now I’ve used VMs many times, even way before Linux, and the comparison is interesting once or twice. But honestly docker is cool and useful without knowing anything about VMs. So if you want to learn docker and only docker you are going to be subjected to the mind numbing comparisons to VMs over and over.
Another complaint…often these YouTube docker video explain how to use docker on Windows or Mac…you know…the important OSs. Let’s just forget about the fact that docker was created on and for Linux.