Emotions in itself are a complicated minefield.
Duncan didn't have much experience with dealing with them. He was blunt man by nature. He didn't have the nuance or the wide range of emotions. So, he didn't have much exposure when coming to dealing with them.
However he understood base emotions like anger, frustration, happiness, relief, sadness and so on. So, the first step he tried to do when trying to alter the emotion associated with his experience was to try to attach another emotion to it and let it dominate the despondency that was being magnified severalfold.
Duncan tried to work with positive emotions like happiness and joy first. However, the inherent emotion of the memory was that of a negative light. He had been feeling pretty down and out during those times. That's why he tried to forget them by drowning them in wine. Trying to alter such a base component was not possible for him at this time.
