One common obstacle for this is perfectionism: no matter how well you did, you could have done better. Perfectionism can make us afraid to look at our own work with pride and recognize, much less celebrate everything that we have achieved.
Perfectionism can make us less motivated and devalue our achievements, because we feel that they are not good enough or do not fit the internal bar that we have set. This means that even when we do well, we do not recognize our achievements but instead focus on the negative aspects, which leads to disappointment and, due to this, a dip in dopamine and a loss of motivation