The beauty of life is, while we cannot undo what is done, we can see it, understand it, learn from it and change. So that every new moment is spent not in regret, guilt, fear or anger, but in wisdom, understanding and love.
Your time is limited, don't waste it living someone else's life. Don't be trapped by dogma, which is living with the results of other people's thinking. Don't let the noise of others' opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become.
The more constraints you have, the more creative you become.