It’s naïve to regret. Making mistakes and facing hardship are crucial aspects of life as without struggle we could never grow.
Not only do such moments allow you to learn more about yourself, but more importantly they can be very revealing of the inner essence of your being.
Even though it may hurt to brood over painful memories, there is sometimes a rather unforeseen sense of satisfaction in looking back on how far you have come and know that you are a better person after having lived through the adversity.
I may want to forget at times, but I choose to remember.