Rebbe Nachman of Breslev teaches (Likutei Moharan I:64) that Hashem created the world in order to reveal His mercy, because if He hadn’t created the world, He would have no one to whom He could reveal His mercy.
What do we learn from Rebbe Nachman’s teaching? We come to the conclusion that if Hashem created the world and all the creations therein in order to reveal His mercy – and you and I are His creations – then Hashem created us in order to have mercy on us and to show us His mercy.
With this in mind, each of us has to tell ourselves:
1)Hashem created me in order to have mercy on me and to show me His mercy;
2) Everything that happens in my life from A to Z is a result of Hashem’s mercy on me.
3)Since everything Hashem does is mercy for me, I have to thank Him for everything that happens in my life.
That's what Purim is all about - Hashem does fantastic miracles and saves our entire nation from annihilation, not because we deserve it, but just to show us His mercy. Have an easy fast!