The fundamental answer is that we write because we are consciously or subconsciously urged to do so. It is very much like going to the loo - sometimes its relaxing, sometimes easy, sometimes difficult but always - a relief.

The intrinsic reward of writing, i.e. satisfaction of saying whatever it is that wants to be expressed, is because letting it out gives relief, even a kind of freedom - o.k. feel better now, eve if that was uncomfortable or not as neat and tidy or complete as I would have preferred.

Then, just as your digestive system and its responsive increased intensity diminish and cease to push you, so your mind can clear, at least momentariy, and you can 'move on' - as they say.

Take care. Stay safe. ☮️