House of UIster put it nicely regarding Superman.
Morrison's work pushes you to attempt to accept things that you know you're unable to. It's almost like he is writing a "Doctor Who" episode with the terminology and "technospeak" that he uses in his work. It can throw people off. He explores big ideas and goes on tangents that are hard to follow. As has been brought up in the thread before, his work isn't for everyone, which is why you have a lot of fans like me that absolutely love him, and a lot that dislike his work. He seems to be a polarizing writer.
This is probably why I love Jonathan Hickman so much. He writes like Morrison does.