Do You "Leave School at School?"

In teaching it seems that there are endless opportunities to take the job home, both figuratively and concretely speaking. Yesterday, as I expressed my concern about some kids at my school, a colleague said, "Well, you know. There isn't a lot we can change here. So I work really hard to leave school at school. "
Even though this was a mantra clearly expressed to me by others before, I was a bit taken aback. This teacher is one of my allies in my passionate fight for kids:  someone who advocates and cheer-leads for those in her classroom.  Her comment led to reflection and more reflection. "Can I possibly leave my thoughts about school there as I leave each day?" Anyone who knows me would probably never take that bet!
I wish I had that balance..well, sort of.  I have managed to get much of my job done and optimize my time at school, but my thoughts are often caught up in brainstorming possible solutions for my classroom and my students. Not only do I take the job  home with me, but in the car, to the store, on the phone with fellow teacher friends and on social media like Facebook and Twitter. I think about the kids who may not be "instantly loveable" and wonder how we can reach them and help them believe in themselves. I think about the endless responsibilities we have in a screwed up system bound by politicians who decide who gets the money that will help the kids and even worse, "how" we are to teach and inspire those kids to become happy, healthy engaged contributors to society.

If we all just "leave school at school" how will change ever happen? Teaching is not my job, it's my calling.  But clearly, a balance is necessary so that teachers don't end up sounding like this teacher: tired and worn out on the 101st day of the school year.
How do you keep the balance?