We see that the world is filled with pain and suffering. Why? What purpose does it serve? Nahama d'kisufa, bread of shame, is that the soul was constructed in such a way that it cannot just take and take. A person who has not in some way earned that which he has received, feels a lack of pride and respect. The soul also was created so that it would not be able to take without earning. G-d had to create a situation where the soul will get His hatava, and He had to create another situation prior to that for the soul to earn what it would receive later on. We earn in this world for the hatava, the World to Come.