Serious humans and how we forgot to laugh with life

Laughter for grownups, we are told, should fit the mold of what is socially acceptable, it shouldn't be uncontrollable or wild, it needs to be restrained.
We have to be serious most of the time, and approach life with a stern attitude because there is death and suffering all around us.

People with a happy countenance are looked upon, generally, as frivolous and sometimes, in some extreme cases, unreliable. We put a fence between our lives and joy. There is time for work, commute, study and there is time for laughter.
Our happy muscles got atrophied and along with it our ability to enjoy life as it comes.
Our grim attitude towards life, smothered the kid inside us. We exchanged loose casual outfits for unwieldy attires and cramped shoes. 

We swapped our affable smile for an antagonistic, pensive frown.
We became edgy and stressed, eroding in the process our mental and physical health.
Babies learn while laughing, adults learn with a frown plastered across a wavy forehead making a chore of the learning processs and adding unwarranted layers of complexity to their existence.