Pluralistic ignorance
In social psychology, pluralistic ignorance is a situation in which a majority of group members privately reject a norm, but go along with it because they incorrectly assume that most others accept it. This is also described as "no one believes, but everyone thinks that everyone believes". In short, pluralistic ignorance is a bias about a social group, held by the members of that social group.
Foolishness
Foolishness is the unawareness or lack of social norms which causes offence, annoyance, trouble and/or injury. The things such as impulsivity and/or influences may affect a person's ability to make otherwise reasonable decisions. In this sense, it differs from stupidity, which is the lack of intelligence. An act of foolishness is called folly.