The past is unchangeable so it is futile to reflect on it unless you are making sure you do not repeat past mistakes. The future is but a result of your actions today. So learn from the past to do better in the present so that you can succeed in the future.
Even more specifically, live in THIS moment.Even 10 minutes ago is the past. If you live purely in this moment you will always be happy because there is nothing wrong in this split-second.
Dawn to Dusk 