All of this is based on the self-discrepancy theory of the the three selves: the actual self, the ideal self, and the ought self. The actual self is what a person believes themselves to be now, based on current attributes and abilities. The ideal self is comprised of the attributes and abilities they’d like to possess one day—in essence, their goals, hopes, and aspirations. The ought self is who someone believes they should have been according to their obligations and responsibilities. In terms of regrets,
Source: How to Avoid a Life of Regret