In life, you are going to be mistaken. You are going to be disappointed. You'll put your best intentions out there; your heart, and all the good you pour into it, and yet, people will still let you down. You will fail yourself and you will completely miss the target. But do not fret, for so long as you continue to endure, these trials and errors will one day become stepping stones to a success so great that no man (or woman) can dare to ever take that away from you.
Persist and endure - not just to survive, but to be a beacon of truth, wisdom, love, goodness and light. Do not absorb the pain and hurt you experience, just let it pass through you and empower you to do better next time.
One of the tenets of evolution is to grow, not only in raw, robot-like knowledge and circle-jerking intellectualism, logic and technological achievements, but to be better in our humanity; our decency as people in our society - improving upon our values, virtues and ethics, especially toward each other, the environment and the animal kingdom. Evolution should be about an overall gain and not just blindsided to one avenu.
Don't focus so much on how much it pains, focus on how you can swing things around for the better.
Life is boring living a Van-Gogh-like-depression; See color in the dark and if you can't, make it so. Creation doesn't shut off because of your needy-pitiful thinking. Reality is still quite amazing.