Regrets

Have you ever come to a point in your life where you look back and just want to kick yourself because you could have made better choices and ended up happier?? I seem to do it all too often. I'm not talking about huge things like schooling, who I married, having/not having children. It's little things like "I should have done that project 2 months ago instead of being in a panic to get it done on time". When will I learn?