Don't forget that you are the result of all the past sensory interactions that you experienced in your whole life, people you interacted with, books you read, advertisements, songs, news headlines, etc. Even if you think you don't remember them, at one point in your life it was processed by your brain and may have changed some posterior decisions you made, thus making you what you are now. Since I realized this, I am…
The thing is when we read, particularly in growing years, the expectation is that we would remember most of things from the book and apply it somewhere else, ex. in a discussion "...agree, the same I gathered from this excellent book that I read couple of years back...".
And frankly, I'm bummed by it still. I read a lot but when certain situation comes I cannot remember things & facts vaguely, even though I had finished 300 pages of that page turner in one night.