Man contains total control over his will and desires:

Our sages teach us that all that is required of man to be successful in serving G-d is for him to nullify his will and desires in face of the will and desire of G-d. This means that one who has wills and desires for forbidden matters should simply not desire them, and that if one does not have any will or desire to perform the positive commands, then he should simply choose to desire them. Meaning, that he should train himself to desire that which he currently doesn’t desire and train himself to not desire that which he currently desires. Through doing so and nullifying his will he transforms his nature from bitterness to sweetness. [This teaching sounds like a fantasy. Is it really that simple to just press a button and stop liking ice cream and press another button to desire broccoli and spinach? Control of one’s lusts and wills is the battle of life, takes much fortitude and sacrifice, is filled with failures, and is certainly not like the turning on or off of a switch. How then does one actually perform and live up to the above teaching?] The secret behind understanding the above teaching is understanding that the will of a person contains the ability to control the entire body. With proper will and desire, one can turn and change his nature, and nullify his personal wills to the wills of G-d. The power of will which is found in the soul is higher than the power of choice. For example, although a leg may not want to be placed into hot water, a person can choose based on his will to force his leg inside despite its protests. The reason for this is because will is even higher than choice and intellect and can control them.

• In Chabad leadership history:[1] The above teaching of the Alter Rebbe finds an interesting historical relation of the following episode: After the passing of the Alter Rebbe there was dispute amongst the followers as to who should take the mantle of leadership; his son the Mittler Rebbe or his prime pupil Reb Aaron Strashela. The brother of the Alter Rebbe wrote the following letter to Reb Aaron Strashela to try to persuade him to back down from his candidacy: “Why are you causing discord amongst the Jewish people. Even if you feel that you are the one being persecuted did we not hear from the Alter Rebbe that all of the suffering of the world is only considered suffering being that it is against one’s will and pleasure [and to solve one suffering all one has to do is simply remove his will and pleasure from the matter that is causing him the suffering]. So, why is it that you desire to receive pleasure from people being close to you and choosing you as their leader, due to which you feel suffering if you do not receive that what your heart desires. All you have to do is swerve your will and desire to sit in seclusion and then you will not have any pain and suffering from people not choosing you as a leader and on the contrary, you will have pain and suffering from them trying to anoint you.”
• The divine lesson: The most important ingredient necessary for us to battle bad habits and desires is to train ourselves to dislike them. For example, rather than face the challenge of self-control every time one sees chocolate, contemplate matters about chocolate and the adverse health effect that it can have and hence one can remove his desire from it all together. Finding a way to change one’s will is the permanent method to bring a lasting change on the ground.

[1] Sefer Hatoldos Admur Haemtzai p. 90