Deception can involve dissimulation, propaganda, and sleight of hand, as well as distraction, camouflage, or concealment. There is also self-deception, as in bad faith.
Deception is a major relational transgression that often leads to feelings of betrayal and distrust between relational partners. Deception violates relational rules and is considered to be a negative violation of expectations. Most people expect friends, relational partners, and even strangers to be truthful most of the time. If people expected most conversations to be untruthful, talking and communicating with others would require distraction and misdirection to acquire reliable information.
A significant amount of deception occurs between some romantic and relational partners. It also forms a vital part of psychological warfare in denial and deception.