With most things in life, we learn from our mistakes and are able to apply this learning again in the future. The one area in life where this is not the case is parenting. You learn from your mistakes along the way, but unless you have 12 kids, you can't apply this new knowledge again. Once childhood passes, it's a done deal. No going back!
I find myself lamenting all the years when I was actively alcoholic and dysthmic*. I was never an abusive parent, and I did the best I could, but I was not as present as I am now. Now that I am recovering and moving in the right direction, my children are 23 and 15 years old. I know better, but I can't do better. I can't re-do their early childhood years, and that is my biggest regret in life!
I know, I know. I need to let go and accept that the past is unchangeable, and that the only thing I can control are my actions in the present...but still, it makes me sad.
*Dysthymia is a low-grade, long-term depression. For more on dysthymia, see: http://www.mayoclinic.com/health/dysthymia/DS01111.