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

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.

Instead of relying on expensive marketing, habit-forming companies link their services to the users' daily routines and emotions.

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

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

If users are not doing what the designer intended (when users are investing time, effort, etc in your product), the designer may be asking them to do too much.

Products with higher user engagement have the potential to grow faster than their rivals.