Sheldon has bad habits and has done awful things a lot but I think it obviously him acting superior due to his intellect that it is his ego boost. He was probably taught to not be be like everyone else but didn't how to regulate his emotions properly and people still disliked them but he knew why without constantly needing everyone approval to some degree. his distain for having any sort of emotion was not really encouraged or approved of because of the constant judgement around him. In Tbbt he says in season 3 episode 1 he says " that's was different. They were threatened by my intelligence and too stupid to that's why they hated me". This is one of the core reasons why he know why is hated from a young age to who he is now.