Licking the spoon after we use it, I believe, is a learned behavior. We do not pick up the spoon and use it to do our bidding with sole intention of licking what remains yet we may find ourselves waiting in anticipation of the sweet pay off nearly every time. Oddly enough we can see this behavior carried over into other parts of our lives from time to time.
If we set out to help someone and notice that we are anticipating praise or reward in return we are essentially doing the same thing. It is not all the time that an individual sets out to help someone and finds that he or she is caught up in anticipating praise or reward. If we find that we do this more often than not, we could consider evaluating our behavior to see if it is worth modifying.
I wish for you happiness, well being, and freedom.