Habit as the intersection of knowledge, skill, and desire
"For our purposes, we will define a habit as the intersection of knowledge, skill, and desire.
Knowledge is the theoretical paradigm, the what to do and the why. Skill is the how to do. And desire is the motivation, the want to do. In order to make something a habit in our lives, we have to have all three."
(Stephen Covey, "The 7 Habits of Highly Effective People", Australia:The Business Library, 1989, p 47)