I still do not know what impels anyone sound of mind to...

I still do not know what impels anyone sound of mind to leave dry land and spend a lifetime describing people who do not exist. If it is child's play, an extension of make believe - something one is frequently assured by people who write about writing - how to account for the overriding wish to do that, just that, only that, and consider it as rational an occupation as riding a bicycle over the Alps?