Not always easy, but always worth it.

Raising small children is a difficult commitment, a commitment that, if taken seriously, is 24hrs, 365.  I've recently heard from a lot of mothers who "can't handle it," and "it's just too hard", and "I need a serious break".  Maybe there's something wrong with me, but I thrive off spending as much time as possible with my daughters.  At eight months, and three years old, it isn't always a cakewalk, but I find myself sincerely missing them every time I'm away from them, and loving all the minutiae that goes with raising babies.  My eight month old squeals when I come home from work, and reaches for me as only a baby can.  Her chubby little fingers open and close, until she has wrapped her little arms around my neck, and nuzzled her head into the curve of my neck.  My three year old loves to show me all the wonderful new things she can do.  She begs me to read to her at least twice a day, and we love making imginary concoctions in her little kitchen.  (She baked a lovely "crème brûlée" in her little Le Creuset ramekin.)  They're only going to be little for a little while; I'm maximizing all our experiences, and taking advantage of the fact that I am still the most important person in their lives. 
While it's not always easy, I have to say that the challenges fade from my memory, almost as quickly as they occur, and it is the instances of perfection that cement themselves in my mind. 

Tim says it's because I have the "mom gene."  I'll take it as a compliment.