Companies leverage two basic pulleys of human behavior to increase the likelihood of an action occuring: the ease of performing an action and the psychological motivation to do it.

To initiate (user) action, doing must be easier than thinking.

Like flossing, frequent engagement with a product, especially over a short period of time, increases the likelihood of forming new routines.

For an infrequent action to become a habit, the user must perceive a high degree of utility, either from gaining pleasure or avoiding pain.

Fogg states that all humans are motivated to seek pleasure and avoid pain; to seek hope and avoid fear; and finally, to seek social acceptance and avoid rejection

You'll often find that people's declared preferences - what they say they want - are far different from their revealed preferences - what they actually do.

Habit-forming products often start as nice-to-haves, but once the habit is formed, they become must-haves.