In a famous experiment, students were asked to take a lemon home and to get used to it. They seemed to have bonded.
Habit forming in humans is reflexive.
We change ourselves and our environment in order to attain maximum comfort and well being. It is the effort that goes into these adaptive processes that forms a habit. The habit is intended to prevent us from constant experimenting and risk taking. The greater our well being, the better we function and the longer we survive. In the object of the habit we see a part of our history, all the time and effort that we put into it.