Altruism (or selflessness) is concern for the well-being of others. A truly altruistic act is something done completely for the benefit of another, without concern for the self. It usually involves sacrificing something (time, effort or possessions), with no expectation of receiving anything in return (including recognition for the act of giving). It is considered a virtue in many cultures and a basic aspect of most religions. It is the opposite of selfishness.