Prior to the Birkat haMazon we customarily recite the Shir Hamaalot which proclaims, “When the L-rd will return the exiles of Zion, we will have been like dreamers. Then our mouth will be filled with laughter, and our tongue with joyous song.” G-d could have just given the Jewish people happiness and pleasure right away, but he said that it is not coming right way. The reason it says it this way is because it gives the Jewish people something to look forward to. If you do not look forward to happiness then in stagnant moments you will have little to live for. This is why it says when the L-rd will return from the exiles of Zion, we will be happy in many different ways. If you already are satisfied with your life you must continue to strive to improve yourself and be happier. We should always be looking forward to happiness. The principle you should live by is that you should look forward to better things in life; even if you think you are already happy and life is great you should always strive to be better. 

haggadah Section: Bareich
Source: Original