Friend of mine once said to me, "If you have a distaste for the smell of shit, force yourself to smell it until it doesn't bother you anymore." I doubt he meant this in a literal sense, although the image of a Sufi master literally forcing the student to eat hir excrement for the sake of desensitizing the pupil to the corrosive elements of the world and hir own personality- (and primarily for what I would imagine to be shits in giggles, pardon the pun!) is an appealing one for comedic value alone, this is something I wouldn't take literally if I were you.
Many cultural biases or triggers we share collectively seem to provoke irrational fear, anxiety or to trigger the "panic button" response in human beings. It's somewhat of a hardwired physiological phenomenon that has basis in our evolution- That which causes pain or discomfort is to be avoided. The child is burnt by a stove, he or she learns not to touch it again. We associate with individuals who are perceived by us to be untrustworthy, and due to our past experiences we establish barriers or walls towards people who seem to be of the same disposition in the future. If you have a bad experience with any element of life, you will tend to avoid it to prevent yourself from being put through the same pain or burden you have suffered before.
