If you could go back in time, once, and change a single thing – what would it be?

Nothing, cause if I changed anything I would not be who i am, where I am with the knowledge i have and the people in my life.. my past was my teacher, I learned from it good and bad, my present is my chance to be happy and my future is mine to grab and make the best out of it. But if I changed anything from my past none last of this would be real. I am stronger, wiser and more caring for it so I would not change a thing