Think about the last time you were 50/50 on a decision.  You obviously remember making one choice, but according to the Many Worlds theory, you also made the OTHER choice, and there is a separate universe where you are living a similar life except for that one small difference.  This concept is perfectly exemplified in the Rick & Morty episode “A Rickle in Time”, which The Brain Trust use as a template to describe this crazy concept in more detail.