Obviously, it's good to strive for creativity and novelty in your work, but you also have to maintain a sense of perspective: if you've set your goals so high that your definition of "achievement" is isomorphic to "originality", then you're probably in for a lifetime of disappointment. It's a hard problem to be original -- there are a lot of other people in the world, and most of them are trying to be original, too. In fact, being original is a lot like being famous, because you can strive for it, but your success is largely determined by what other people do; it's probably bad to condition your self-esteem on the actions of other people.
For what it's worth, here's my half-formed philosophy: you have to do whatever it is that gives you a sense of personal satisfaction and contentment. Your accomplishments don't have to be great; they don't have to be original; they don't have to make you famous. As long as you can look in the mirror in the morning and feel excitement about the day, you're doing pretty well.