I find this subject really interesting because once you understand that everything you perceive is actually false (humans weren't made for objective or "real" thinking), you realize you can basically gaslight yourself into believing and remembering things that didn't happen.
For me, the best example is when I was around 13 years old and I found a normal 3-leaf clover.
I really wanted to find four leafed ones (obv), so I made it into that. After shifting the leaves and adding another one, I compressed it in my notebook under a heavy book for a couple days.
Once I took it out, I found out that it was indistinguishable from a naturally four-leafed one.
I believed that lie I made up so much that only after 4 years or so I remembered it all was fake, and that really shook my understanding of memories and lived experiences.
Now, after some """training""" I can make myself believe something actually happened, which is quite unsettling but interesting nonetheless.