A fatalistic/pessimistic person might ask: "Why do any of this?" To such a person I would reply: Not because it is needed, wanted, or deserving. But because having goals is a part of life, I chose these over others as they seemed most appropriate. In short I do this because, after some consideration, it seems appropriate. In the human condition, without full knowledge or control, this may be the best conclusion, and ultimate justification, one can arrive at. There are days when I feel like a leaf caught in the current of a mighty river. I know how I got here, and I have an idea of where I am going, but altering my course seems more of an illusion I create for myself than a real possibility. And though I may know where I am headed, I do not know how long it will take or if I will ever get there!
One may still ask: Why are these goals appropriate, and not some others? I'd like to think I am qualified and capable of making that determination; I have the average fund of knowledge for a person of my age and social position, which is unsurprising according to the mediocrity principle. PZ Myer wrote a good essay about this principle, which reminds me of the Doctrine of the Mean in Chinese philosophy. I should also add that, consciously or not, I often apply several tests to justify appropriateness, perhaps the most important is "does it benefit my children?"