We all have a self-image, and it is in terms of such a self-image that we evaluate how happy our life is. If my self-image is mainly an academic, then how happy I think I am depends on how successful I am as an academic.
Our self-image can be more or less complex. I can, for example, identify myself just as an academic, but I can also identify myself as an academic, a philosopher, a father, a husband, a poet, a writer, and a cook. According to the psychologist Patricia Linville, the more complex a person's self-image is, the less likely that her happiness in life swings up and down when she does well or poorly at some specific thing. This is easy to understand, for if my self-image has many aspects, then even if one aspect is damaged, my self-image as a whole may still be intact, particularly when I am doing well concerning some of the other aspects.
Of course the matter is not that simple, for it is possible for us to have a false self-image.