Growing up with Zulus, my surrogate father, Dlamini was an Inyanga (a male Zulu witch doctor). He used to perform all kinds of umbhilo (magic). One particular ritual which really astonished me as a child was when he would put small pieces of meat at the end of a skewer and put them into the flames of a fire, claiming to feed his ancestral spirits. He would give a few twitches of the arm and retrieve an empty skewer, much to the gasping amazement of everyone and required ululating of the women attenending.
It wasn't until I was sixteen that another Zulu showed me the trick employed in this practice and although I already doubted the existence of spirits, it served to concrete my thoughts on the whole fake spirit thing.