The stream of thought flows on; but most of its segments fall into the bottomless abyss of oblivion. Of some, no memory survives the instant of their passage. Of others, it is confined to a few moments, hours, or days. Others, again, leave vestiges which are indestructible, and by means of which they may be recalled as long as life endures. 

~William James  (The Principles of Psychology, Vol.1, pg. 643)

Speaking of memories, may I introduce you to an American science-fiction film, Marjorie Prime, that was based on Jordan Harrison’s Pulitzer Prize-nominated play of the same name.