People's belief

chibgyibbilyy

Why do people (you, or your family, for example) believe in things that sound too good to be true and have no proof? (Do your best psychoanalysis here.)
What are the most common faulty arguments used to justify peoples’ beliefs?
What would you say to someone whose beliefs are unfounded and possibly dangerous to their health?
Requirement: at least 1000 words and no Plagiarism.