To deny your past
How often do you lament your past? Wish you'd done things differently? Had regrets? Most of us have our own little ways of finishing the sentence "if only I had/hadn't..." invariably looking back at certain things and wishing they either had or hadn't happened.
The concepts of time and its existence/non-existence can get very deep very quickly, so I will save that for another post, but in a nutshell, most ancient philosophies espouse the idea that life is just one perpetual moment, that there is no real past or future, only an eternal now. A spectrum of time and the idea that there are events that are "behind" us and unknown events that lie "ahead" of us are a construct of the human mind, developed in order to give our life a grounded sense, a little like the way gravity keeps physical objects in order so that they don't float off into the ether. Humans need constructs and paradigms into which we can organise and understand information, and our intellect, although advanced, still struggles with certain things that defy these frameworks.
But if you can imagine for a second that all of time is right in this very moment, you can imagine the perpetual now that we are living in. It's one great big circular movement, rather than a linear one. Everything you have done and experienced in your "past" up until now actually occurred in this perpetual moment. Therefore, everything you have ever done has had a direct influence on your present experience of life. Every. Single. Little. Thing. At the risk of using the sequential time paradigm I've just labelled as a fallacy, every moment has influenced the moment that followed it, and that one after that, and so on. Now, though many of us would feel that our lives aren't "perfect", there are certain things no doubt that we adore about our lives. But regardless of how good things may be now, we still have a tendency to look back and regret. The trouble is, when you admonish that past, you are in fact condemning your present - they are all part of that one perpetual moment, remember? So when we look back and say "I wish I hadn't had a relationship with that person", we are saying that we wish we didn't have our present circumstances. We are in effect saying that we wish that the past had been different, and to wish for a different past means to wish for a different present - is that really what you want?
Mind-bending rhetoric aside, what I want to challenge is your looking back at the past and wishing for different. Even one tiny change to your past would re-write your entire present. You could erase a regretted past relationship, but would you do it if it meant erasing the one you have now? You might wish to make a different choice about a previous life decision, but would you change it if it drastically altered your life now? Usually, the answer would be no. Sometimes there are things we do wish we could change about our present, but the answer doesn't lie in changing the past. Mainly because that would be impossible, but also because there actually is no past - you are living it right now. So if something in your present experience of life is dissatisfying, what are you going to do about it now?