Redheads are "more frightened of dentists"? I thought everyone was afraid of dentists. Except the healthcare industry I suppose.
Some people actually like going to the dentist. Generally people who take good care of their teeth, and therefore have nothing to worry about, may even find it to be a pleasurable experience. Even something like a (gasp) root canal isn't that painful. Root canals are actually substantially LESS painful than getting a tooth pulled... because root canals are only done if the nerve and surrounding tissue are damaged already, and it's the damaged nerve that's causing all the pain, not the procedure itself.
I'm pretty sure that only applies to the Orks in 40K. The red ones DO go faster, though.