'The Impulse': An Exercise

I was doing some reading today and I came across a concept known as 'the impulse'. 'The impulse' is the feeling experienced by a writer (or by others whose hobbies or professions depend heavily on creativity) when he/she is impacted by a situation, in its broadest sense. The author suggested an exercise that is similar to this:
At any moment, when you go about your every-day routine or when you are just taking a simple walk, if you happen to observe a scene which evokes a feeling or a reaction from you, then write. The key, the author describes, is to just describe the scene and not analyze it. The idea is to describe every detail, as irrelevant as it may seem. The idea is to allow your unconscious to write out the scene, meaning that there is no need to make it coherent because that would mean that your consciousness is controlling how you express what you felt. It is key to remove yourself from the scene and stand aback and observe the scene from afar. After describing every detail, then you can begin some dialogue (if the scene has people) and try to make it simple and an unstrained conversation - just whatever you think could have been said. Write for 20 minutes or whenever your 'impulse' is drained.
I haven't yet tried this exercise, these 'impulses' like the make themselves rare in my case, but i will try it and let you know how it went and let you judge for yourself.

I'm publishing this because i think its important to know that not everything has to be planned out or practiced. Sometimes the best in people comes out when you don't have a critical eye on the beginnings of a piece of art.

The book was entitled: The Art of Dramatic Writing by Stuart Spencer