An artful critique focuses on what a person has done and can do rather than reading a mark of character into a job poorly done.
As Larson observes, “A character attack – calling someone stupid or incompetent – misses the point. You immediately put him on the defensive, so that he’s no longer receptive to what you have to tell him about how to do things better.” That advice, of course, is precisely the same for married couples airing their grievances.
And, in terms of motivation, when people believe that their failures are due to some unchangeable deficit in themselves, they lose hope and stop trying. The basic belief that leads to optimism, remember, is that setbacks or failures are due to circumstances that we can do something about to change them for the better.