Do not look back and grieve over the past, for it is gone; and do not be troubled about the future, for it has not yet come. Live in the present, and make it so beautiful that it will be worth remembering.
Purnima or the Full moon day is considered auspicious in Hindu calendar. Since time immemorial, Hindus have believed that the fortnightly cycle of the moon exerts a great influence on the human anatomy just as it affects the water bodies on earth resulting in tides and ebbs. Devotees fast on this day to get their wishes fulfilled.
Not only does it have a religious importance, but Purnima has a little more to do with the human fate. I read somewhere, a long time back, on the full moon day the gravitational force of moon towards the earth, is at its highest. Eventually your deeds and thoughts of this day are more likely to materialize and become true. Hence, on this day one must have only positive thoughts in mind and your thoughts shall become things!