I think working at the battered women shelter. It used to be completely horrifying, at times, now what I see are strong women who are finally standing up for themselves and their children. They may come in broken, but so many leave strong and ready to start fresh.
Of course, it is heartbreaking to see the repeat visitors and those that return to their household because they think that is the best they can do. You just keep trying, hoping that one day, they will understand that abuse does not equal love.