Nothing I've experienced has provided more intense sanctification opportunities than parenting.
I once heard someone quip, "I finally got to the point where I had parenting all figured out. But then? Then I had kids."
So much responsibility falls on our shoulders as their protector, provider, example, comforter, disciplinarian, and teacher.
Thankfully, the Lord is an infinitely more patient teacher than I.
The most effective teachers are those who have mastered their subjects themselves. I find myself floundering and frustrated again, because I can not seem to "get" those things which I'm trying (unsuccessfully) to teach: kindness, self-control, happy obedience, true brokenness over sin.