This is a question worth asking. Without a purpose we're just running on a gerbil wheel.

It takes as much time and energy to flail at the wind as it does to accomplish specific tasks. Maybe more, since real tasks have a start and finish, whereas flailing can become a habit that never ends.

Having said that, I think self entertainment can be a legitimate purpose, as long as you can set it aside when real tasks demand attention. The difference between choices and addictions is the ability to refrain from them when necessary.

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0