As we get older, we learn that those who shouldn't have let us down will also let us down. You will hurt yourself, and you will hurt others. You will fight or even fall in love with your best friend and cry over time.
So, take too many pictures, laugh a lot, forgive freely, and love as if you weren't hurt. There are no guarantees, no timeouts, no second chance in life. You live life to the fullest, tell someone what it means to you, scold someone, talk, dance in the pouring rain, hold someone's hand, comfort a friend, watch the sunrise and fall asleep, sleep late, face Flirt and smile until it hurts. Don't be afraid to take risks or fall in love.
The most important thing is to live the moment, because every second of being angry means you are never get back that second which could bring happiness in your life.