"Charlie" wrote a post on the New York "What's my craving" board asking why do you "have" to wash chicken before cooking it? (It can't be for safety reasons, since presumably the cooking process will kill any microorganizsm that may be on the surface of the chicken.)
That got me thinking, how much of what we do in the kitchen is routine as opposed to based in any way on food safety or flavor?
Case in point... many people soak all dried legumes but some, especially lentils aren't really helped by this.
Also, washing rice is supposed to "clean" it. but what it actually does is remove the layer of vitamin powder that is aded to almost all "enriched rice".
Harold McGee in his "On Food and Cooking" sites numerous other examples.
What cooking myths are part of your routine?