I was first introduced to Lawrence Kohlberg's 6 Levels of Moral Development through Rafe Esquith's Teach Like Your Hair Is On Fire, and was immediately drawn to it. I've used it every year I've taught since, and each year it's taken a more central role in my social/emotional teaching. The stickler is Level 2: I do something good, because I get a reward. Many classrooms are based on stars or bucks or stickers or whatever. But it's a facade, because there are 4 levels of moral development that are being shut out by introducing rewards like these, and what's more, if the desired outcome isn't crystal clear, the reward system will flatly just not work.
One of the best TED talks I've seen lays this out very succinctly: