Sometimes people believe there is some relationship between events, variables, etc., even though none really exists. This is known as the illusory correlation and it occurs in everyday life as well as science. For example, you may have had some experiences with lawyers, some good, some not so good. It is possible that you only recall the bad experiences (maybe where you felt as though you were lied to by the lawyers) which leads you to formulate the conclusion that all lawyers are liars. Thus, you could come to associate (wrongly?) lawyers with lying, and conclude that all lawyers are liars.