It is impossible to do anything unless you have desire. Even merely to say something, you must first have a desire to speak. Likewise, in order to do something, you must first have the desire to do it.
The strength of the person’s desire is created through being confronted with an obstacle. The purpose of the obstacle is to increase one’s desire to accomplish the task.
We are held back from what we want by obstacles whose only purpose is to increase our desire.
Avraham Greenbaum, The Essential Rabbi Nachman