Chazal tell us (Shabbos 88a) that even though Bnei Yisroel were to some extent forced into receiving the Torah (for Hashem held a mountain over their heads) nevertheless, they reaccepted the Torah wholeheartedly in the days of Achashveirosh. Rashi explains that the miracle performed for them caused an extraordinary amount of love toward Hashem, which was the impetus for their wholehearted acceptance of the Torah.
Rav Wolbe points out that the Ba'alei Mussar note that love is the thread that runs through all the mitzvos of Purim. The reading of the Megillah is in reality a recitation of hallel and it should bring us to a love of Hashem. Mishloach manos and matanas l'evyonim are ways to breed love between man and his fellow man. Even the seudah on Purim is an expression of love toward oneself.
Moreover, there is a mitzvah to become intoxicated to the point that one can no longer discern the difference between the cursed Haman and the blessed Mordechai. In other words, we are to love the wicked person just as we love the righteous, and reserve our hatred for his evil deeds. Though it is generally hard to separate a man from his actions, on Purim we are to make a special effort to love each and every one of our brethren.