There was once a Yid who set out on a journey, intending to commit a grievous עבירה, taking with him five hundred gold rubles which he had amassed. While traveling, he suddenly heard the heartfelt crying of a family in trouble; they were being evicted for not having paid their rent. His pity aroused, the Yid gave them all the money he had with him, with which he had planned to do the עבירה. A great tumult took place למעלה, and the verdict was made that whatever this man would decree would materialize. However, to ensure that this privilege not be misused, they decreed that he become a שיכור.
Once, a terrible צרה came unto the world, so the בעש"ט sent his talmidim to beg this drunk Yid to intercede and ask for רחמים. Arriving at his place, they found him שיכור, and had to try a number of times until they caught him before drinking. They presented their request and he successfully abolished of the גזירה.
The חידושי הרי"ם would conclude: Purim is a day of עת רצון, when every Yid can be פועל to no end, and the drinking should not disturb us from accomplishing what we need.
(שפתי צדיק אות נ"ג)