Shias: Why do you ociate partners unto Allah?

Dear Shias, i understand the poster of this question had his facts wrong. I am sunni and i have a few questions for you. I hope i dont get replied with hatred bcuz this is only for knowlodge. Why do shiaas hate some sahabas eg. Omar, Aisha radiya allahu 3anho. Why do shi hit them selves on 3ashoora? dont they know that in the quran it clearly says not to do anything hurtful to our bodies and for funerals not to get deppresed to that limit? Why do u believe that angel jibril made a mistake and made prophet muhammad (S) the prophet? dont you know that it clearly says in the quran that Angels are not capable of making a mistake. and to the replyier saying that sunnis believe in a new quran called bukhari, plz can u get ur facts straight? we definetly do not believe in a quran like that. Thanks