I started working out when I was 16. My parents were fearful of my weight at the time, I was 6'0 265 lbs. and very obese. The told me, "Jeez, your as big as a barge!" They thought insulting me would push me to change. lol. In a way it did. I used much of the pent up rage and angst I felt at the time in the gym and about two years later I was still 265 lbs but no longer obese.

The way I see it, if improving the outward image of yourself help contribute the inward image as well (to a point). In my opinion it also pushes you to be more motivated in other aspects. It pushes you to not be lazy.