The title of this talks is inspired by the Timur Kuran’s book entitled “Private Truths, Public Lies. The Social Consequences of Preference Falsification”. During my presentation I will talk about the idea and real-life examples of Preference Falsification (PF). Furthermore, I will propose a simple binary agent-based model, which allows to describe PF by introducing two levels of the opinion: the public and the private one. Finally, I will discuss how PF can help in explaining social and political dynamics.