It seems rather intuitive.
Follow the heart to happiness.
Follow the herd to dissatisfaction.
This is what researchers at the University of Rochester claim to have found in a small study examining intrinsic and external forms of motivation in 147 recent university graduates. Students that focused on achieving personal goals self-reported as happier than those who focused on socially defined goals such as wealth, status, or fame.
While this study doesn't prove anything, it does suggest something we all feel, that chasing the dreams of others is often frustrating and unfulfilling. A similar study on older subjects, people with a lifetime of experience doing both, might show something else entirely, that over the course of a lifetime, even personal achievements are trivial concerns. As Dolly Madison said at the age of 80 to a young niece:
There is nothing in this world worth caring for.