I remember the first time I worked out that life's not fair. There's no over-arching justice to ensure that just because someone beats be at one thing they won't beat me at another. Nature as a whole has no sense of fair play. The best you can do is get on with life.

Having said that, if you treat people well you often find that their sense of fair play gives you a safety net.

But always remember:

    "Life is pain, highness. Anyone who tells you
    differently is selling something."
 
        — William Goldman (The Princess Bride)

ADDED IN EDIT: I've just been checking - although the line is in the film, it's not in the book.