Question

what is normal are decided by the society we live in

Answer 1

yes it is actually, to know what is normal first you have to learn what is "abnormal" , abnormal is simply just a label that is given to a behaviour which is deviant from social expectations. Abnormal behaviour, thoughts and emotions are those that differ from societal norms. Society's values may change over time so the concept of 'normal' . It is an unauthorized, non-declared assumption that socially accepted behaviour is not abnormal, and that normality is nothing more than conformity to social norms.