I think most people have an intense psychological need to feel they are ‘good’. After all, if we are not ‘good’, we probably have extra work ahead of ourselves to set ourselves straight ethically and at the very least, preserve our social standing. Some of us do moral calculus all the time in order to stave off guilt and justify our current course of action. The mature among us value intellectual honesty when doing this, and try to avoid jumping to convenient conclusions.
With all this being said, I think a lot of us too often fall short of being intellectually honest because we really value perceiving ourselves as being ‘good’. For example, just consider the most common argument against moral philosopher Peter Singer’s main point in his famous essay “Famine, Affluence, and Morality“. Many people reject his argument because it’s too demanding–not because its clauses are flawed or the logic tying them together is faulty, but because the conclusion implies just about everyone is currently not as good as they think they are.
If people could better suspend their moral self-judgment, they wouldn’t fall into this sort of trap. There is a time and a place to deal with moral guilt (hopefully by altering our behavior), but it shouldn’t be while we are trying to determine moral truth.
If this sounds trivially obvious, when is the last time you felt you were a moral monster? When did you last feel heavy guilt for spending resources on yourself that could be better allocated to reliably avert a lot of others’ suffering? If you’ve never felt that guilt, you may be putting the cart before the horse in your moral reasoning.