Life.

In life we do things - some we wish we had never done, some we wish we could replay a million times in our heads, but they make us who we are. and in the end those experiences shape every detail about us. if we were to reverse any of them we wouldn't be at the exact place we are today. so just live, make mistakes, have good times, cherish the memories, but never second guess who you are, where you've been, and most importantly where you are going.