"Part of the idea behind Purim is the idea of masks.
"In the Megillah, there were several people that wore 'masks'.
Our sages say that Haman was really just a simple barber and he 'dressed up' as the great Haman.
Esther herself hides her true identity and wears a 'mask' in her role as the queen.
In fact, the story itself is one that tells of miracles that are “hiding” and could be interpreted as a series of coincidences.
Nature is the way the world conceals its inner truth and this is seen in the numerical value of the Hebrew word 'Teva' (nature) which is equal in value to 'Elokim' (the name of God that is used when He works through the laws of nature).
The word Teva itself also means 'to drown' and one of the explanations is that nature drowns out the real truth behind it.
Therefore, the miracle of Purim can only be comprehended when one is drunk in order to see things behind the masks.
The real miracle of Purim is not that 'many of the people of the land became Jews', rather that Achashverosh’s decrees caused the Jews themselves to stand up and decide that they were Jews regardless of whatever mask they were wearing."
–Rabbi Adin Steinsaltz
From a talk by Rabbi Adin Steinsaltz, Tekoa Hesder Yeshiva, 2001