Why is it so important that managers, and people in general, should act ethically and temper their pursuit of self-interest by considering the effects of their actions on others?

because giving excessive importance to oneself with no consideration of societal interests leads to disaster for each individual and for the whole society because scarce resources are destroyed

because ethical issues are seldom clear-cut, since the rights, self-interests, goals, and incentives of different stakeholders often conflict

because a manager has no reluctance about communicating an ethical decision to people outside the company since the typical person in a society would think it is acceptable

because if all companies make the right choices, all stakeholders will benefit in the long run