Perhaps I've been thinking about this in the context of my own life lately, but...
What happens when a person doesn't use their gifts and talents to their fullest advantage? Who suffers more -- the individual, or those they could influence and inspire? I feel it's a matter of personal responsibility to not only discover what your gifts are, but to also cultivate and exercise them to their highest impact.
Imagine if some of the great impactors of even the 20th Century hadn't realized their potential? Some have even been discussed here recently -- Churchill, Reverend King...what about Einstein or Gandhi?
Granted, this is sometimes easier said than done (that and, we can't all be great world leaders, alas). Some gifts we innately recognize, and some are discovered along the way -- sometimes with the help and gentle prodding of others who care enough to take the time to pull them out of us. It can also be an incredibly exciting time -- shifting your self-perception as you find out who you're meant to become (maybe this is a patently mid-20s experience, hopefully I'm wrong).
This was inspired by "The Incredibles," and who would have guessed such a relevant lesson would come out of a family-friendly Disney movie?
In the film (which, from an animation standpoint, is sublime), the protagonist Bill, aka Mr. Incredible, must keep his super-human strength a secret. Because of this, he's miserable, he's not firing on all cylinders. He's bored at work, distracted at home -- there's something missing in his life and he knows what it is. When he gets a chance to exercise his might (literally), he comes alive. He's a brand new man, a loving husband and doting father. He knows he's doing what he ought to be -- fighting crime and saving lives.
It is clear to see, in the case of one fictional, animated life, that putting one's talents to use makes life that much more worth living. Seems to me like it probably works that way in reality, too.