Gratitude brings us to Teshuvah

The more that we thank Hashem and see the greatness of his presence, the more that we live on Hashems terms and not our own. When we face the true reality of the world and accept it as it is, we gain the ability to grow. Gratitude brings us to Teshuvah more then anything else. The more we see all of the good things that Hashem does for us the more that we will want to return to Hashem.

from a Shiur by Rebbetzin Heller about the Deeper Meaning of Chanukah on Aish.com