Set value isn't constant, different things have different values to different people and in different situations, for example a bottle of water might cost $0.50 at a grocery store, and $5 on a hot summer day outside, you would never waste $5 on a bottle of water usually, but if you are dying of thirst you would. The water hasn't changed, the situation has. It all depends on the situation.

So next time you are feeling bad about yourself, or can't make the most of your talents, you might just be in the wrong place or situation.