If you have proper methods and rituals in place.. you cannot forget. Certain people, places and events stand out in the brain, things that are “abnormal” or outside of what we normally experience, this is a common trait in everyone.
“9/11” for instance, you can’t “forget” it.. No matter what you try, something in your life is now soaked in the distorted repetition of imagery, propaganda and so much conflicting “information” that no one truly knows what happened except the perpetrators themselves, the energy of it infused into the fabric of our society.
The perpetrators of 9/11 knew and understood this very well, and while the event itself can not be forgotten or ignored, it can be surrounded with controversy, deception, nonsense and argument indefinitely, not only to constantly shift blame or suspicion but to confuse and distract the population from discovering the true motivations behind it.
We can use this fact to help us remember positive things too, even incredibly long lists, vast numbers, lists of dates, times and places and other things seemingly impossible to memorize. It’s actually not hard to get very good at basic usage of it and it’s especially useful in business meetings if you can remember tiny details about someone. Things that are important to them; their childrens’ names, where they grew up or some of their favorite things, it creates an instantly stronger connection with them.
A common familiarity or affinity with something is what I think is what draws people into groups of all types from vast or loosely defined groups like political or religious affiliations, etc.. to familial bonds, but ideally we feel the closest bonds to those we feel help keep our current illusions in place.