A few years ago, psychologist Nancy Etcoff wrote a piece for Science & Spirit magazine in which she explained that "while feelings of happiness change from day to day, depending on the circumstances, people seem to have a stable midpoint to these variations, a general level of happiness to which they return after momentary irritation or elation fades. Scientists call this the 'hedonic set point' or happiness thermostat."
So I was interested to read about a recent study from a group of researchers at Northwestern University who suggest we have a set point for morality as well. They ran a bunch of experiments to see how our sense of moral self-worth affects our behavior.
According to the scientists, people who behave immorally in one aspect of their lives tend to "cleanse" themselves by performing good deeds in other areas. But their model goes further, as a write-up of the research reports:

Other studies have shown the moral-cleansing effect, but this new Northwestern model shows that the cleansing also has to do with restoring an ideal level of moral self-worth. In other words, when people operate above or below a certain level of moral self-worth, they instinctively push back in the opposite direction to reach an internally regulated set point of goodness.