I have a hypothesis that there exists a tradeoff in the mind between the tendency to think big,bright ideas and being able to recall them later.
Explaining this further, the brighter and more revolutionary the idea you just thought of, the lesser are the chances that you will be able to recall it by the time you decide to work on it.
But with maturity and practice, this tradeoff must fade off, that's why people who are in the profession of implementing ideas liek artists, writers, musicians produce the best work of their lives after much much practice.
To cite a famous example, Douglas Adams, once was presumably high and was having a lunch conversation with his friend, during this conversation, Adams told him three ideas, one of them was the book “The Hitchhiker’s guide to the galaxy”.
They realised the importance of these ideas and knew instantly that they were profound.
When they met later, they forgot the two ideas except for the "Hitchhiker's guide to the galaxy" one.
None of them was able to figure out, what the rest of the ideas were, except for the fact that they were equally revolutionary.
I believe that the most true idea ever thought by humans was the idea of writing about a HitchHiker's Guide To The Galaxy.
— Saurav Tomar (@sauravtom) March 29, 2015
Now imagine what the other two ideas might have been.
Source : A documentary titled "Life, Universe and Doughlas Adams" https://www.youtube.com/watch?v=OHJLNrDzYm0