A thought from R. Tzadok of Lublin:
Even when a Jew is self-indulgent, and is a contrarian to G-d and his Torah, in truth, in his heart of hearts, he’s entirely focused on G-d.
The Talmud (Eruvin 65b) says that you can recognize the truth of a person when he is drunk.
Additionally, the Talmud (Pesachim 68b) states that on Purim one must also have personal pleasure.
What this conveys is that even when a person believes that they are only concerned with their own pleasure, in truth, all that they do is for G-d.
Even at a state where the person declares cursed in Mordechai and Blessed in Haman – saying on the left that it is right, and the right that it is lefts, nevertheless, the essence of his soul cleaves to G-d.
(Machshevet Charutz pg. 29)