In The Expectations of Morality, Gregory F. Mellema develops the idea of moral expectations. (I didn’t think the book was great, but the idea was key ideas were interesting.)
There are things which we are morally expected to do (or not do) which we are not morally obliged to do. The book does not do a good job of saying what is meant by moral obligation. The working definition I extracted is that if one fails to fulfill moral obligations then one is guilty and deserving of punishment (morally, although not necessarily legally). If one fails to fulfill a non-obligatory moral expectation, one is blameworthy and deserving of some degree of censure, not punishment. That said, in my working model, these concepts form a spectrum that spans from the merely disappointing to the outright guilty.
The praiseworthy is that which goes above and beyond what is expected. This is also called the supererogatory.
The book does not discuss where moral expectations come from and what makes something obligatory or merely expected. My working hypothesis is that they come from the social contract.
Aside: I’m using the social contract here in the broad sense of the implicit understanding between individuals that allows society to function. It includes explicit rules, including laws, but consists mostly of norms or, in other words, expectations.
Unfulfilled moral obligations violate the social contract. Society, at large, has agreed it has the right impose negative consequences for not fulfilling an obligation.
Unfulfilled moral expectations do not violate the social contract. They weaken it. No negative consequences are due, but some level of disappointment or condemnation is in order.
Going above and beyond that which is required to fulfill an expectation or obligation enriches the social contract. If this leads to a sustained pattern of behavior, it can create a positive sum situation which persistently enriches the social contract. (Which, in turn, may turn today’s “above and beyond” into tomorrow’s expectations.)
Explicitly grounding moral expectations and obligations in the social dynamics of groups removes the Platonic idealization of morality. It places it in messy and contextual reality of human relationships. For those who look for a morality that is universal and unchanging, this may feel unsatisfying. However, after having sat with ideas like this for awhile, I the idea of morality as an emergent property of group dynamics to be empowering rather than limiting. (See Nonzero for an interesting development of this idea as part of a larger thesis; Wright’s The Moral Animal, which I haven’t read, goes into the moral angle more deeply.)