Ariana Grande: Memory Wipe?

Why we cannot remember things that happened in our life?

It is not the ones that lived them?

Why we have different memories about the same thing that happened to us? I am sure this happened to all of us.
We are talking with someone in our life about the same event that we both lived, but we have different memories about what actually happened.
How come?

Memory wipe?
I suggest you yo watch the series Westworld to understand more about this.