You have not lived until you have done something for someone who can never repay you.
Find an opportunity to help someone today who is unsuspecting, and more importantly, incapable of providing you anything in return. This may require a little extra effort, not to find the opportunity, but to find the strength to overcome your natural instincts to focus on your own needs.
But love your enemies, do good to them, and lend to them without expecting to get anything back. Then your reward will be great, and you will be sons of the Most High, because he is kind to the ungrateful and wicked.