Fogg states that all humans ...

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
 Nir Eyal

Quotes from the same author

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.
 Nir Eyal
For an infrequent action to become a habit, the user must perceive a high degree of utility, either from gaining pleasure or avoiding pain.
 Nir Eyal
Reducing the thinking required to take the next action increases the likelihood of the desired behavior occurring unconsciously.
 Nir Eyal
To initiate (user) action, doing must be easier than thinking.
 Nir Eyal
The aim is to influence customers to use your product on their own, again and again without relying on overt calls to action such as ads or promotions.
 Nir Eyal