Sufism
There are some Muslim schools of thought, such as the Wahhabi for example,  who oppose Sufism because they feel it obliterates the difference between God and man and bypasses the common method of salvation as prescribed by their interpretations of Sharia. Although there are non-Islamic versions of Sufism too (generally defined as 'Universal Sufism') puritanical and rigid people in Islam tend to view them with considerable hatred and anger. As a result, we often see a great deal of misunderstanding and conflict regarding Sufism and Sufic practices.