you don't want to use your left hand to hand anybody any element."hand me that piece of paper, will you?" you'd better remember to use right hand because that's what they do there, that's the protocol they use with you and amongst themselves. the reason? somebody told my friend that person was pulling isa's leg or if he was serious. also, handing things out with one hand is seen as a respectful, less assertive gesture, so they put their left hand behind their back. honor this custom by oing the same!