The hamsa or "protecting hand" is believed to be a way of averting and getting protection from the evil eye, or in general, as a way of summoning assistance from the "Hand of G-d". It is believed that the envious glare of onlookers, even without any ill intentions, can cause divine repercussions. it could be considered helpful to wear or display such an amulet from a totally practical point of view - simply to consistently remind oneself of our own fragility and weaknesses, and to help us reflect this realization in our day to day thoughts, speech and actions.