We call it past for the reason it has gone. We were part of it at some moment in our life. It can be good, bad, or mixed. There could be many reasons for it, our relationships, learning, or how we lived it.
Our past gives us an experience. The enlightened ones learn from it and try to get with it in their present life. They don’t get biased. They don’t judge present on it. Our journey of life is constantly moving at a rapid pace. We cannot be two similar situations.