Why do we sometimes mellow out with age?

Sure we do not all mellow out with age but I feel I have and some days I certainly wish I haven’t. I think it just has to do that I have learned the art deciding whether an arguement is worth having.
Although I frequently speak my mind on fluther, in my own life I have learned to avoid conflict if I can. However it wasn’t always so. When I was younger I spoke my mind no matter the conflict it would cause. If someone in the family was creating a problem then I attacked head on.
The good thing was that I would say my peace and people learned not to annoy me. The bad of course is that sometimes it created problems for other people or hurt feelings.
So now I find myself either playing the politician or just avoiding people so no one gets their feelings hurt. Of course I just end up with resentment or just avoid some people all together.
I just really rather not get involved in the drama. I don’t have the stomach for it anymore. I don’t feel like spending the rest of my life involved in other peoples drama.

So does mellowing out mean you get wiser, or simply more indifferent to those around you?
Are you mellowing out?
If so, in what way?