If one is concerned about his life's work, it means that he's concerned about the result, right?

But all we can do is to do one's best. Part of doing one's best is leaving the results to themselves, letting them go, not being concerned about them.

Sometimes it means a difficult decision, going against one's preferences (drinking a bitter tasting tea, folding a good hand in poker, moving to another place at high cost and high risk when we are oppressed), sometimes a compromise. There is more possibilities in life than the one we are attached to.