Seriousness for me is not devoid of joy and laughter, if anything, it is a source of it.

I have yet to meet someone who is or can be more serious than people who truly exercise, talk & spit freely their minds out with full and plain joy and laughter through an indisputable sprinkled Sense Of Humor on their speech.
"Humor is something that makes you think without being aware"

There are many other great & interesting points on your article to which I will try bring on board later. But for now, I just will finish my comment with this quote below. :)

"It is impossible for a man to learn what he thinks he already knows." - Epictetus