Ethical egoism is the consequentialist philosophy which states that morality should be based on self-interest. It is the philosophical basis for many libertarians and Randroids but also got support from Thomas Hobbes. 
 Key ideas
Ethical egoism is based on three arguments:
- That morality is subjective and that it is different for every unique individual.
- That self interest is the origin of all morality.
- That one ought to further one's self interest and that acting against it is immoral.
It is the polar opposite of ethical altruism, the belief that one ought to live for others, and is contrasted with utilitarianism, which is objective. Egoism is subjective, meaning that its implications and conclusions change from person to person and nothing is objectively ethical. This is interesting considering that some of the most vocal proponents of ethical egoism are so-called Objectivists.
Egoism is very appealing to some because it philosophically justifies selfishness, even at the expense of others, and therefore reduces feelings of guilt after acting like a heartless jerk.
Ethical egoism is seen as arbitrary because it values the selfish individual more than other people and there are no objective grounds for this. Similarly racism values one race more than others arbitrarily. 
Those who selfishly refuse to help others later find others will not return favours since they received none. Therefore egoism is not truly in our own interest and a contradiction exists.
“”some misfortune arises and the egoist now needs the unselfish help of another. If everyone is a consistent egoist, the egoist won’t get the help he needs. So in the interests of self-interest, an egoist must reject egoism, at least sometimes; in other words, the egoist must be inconsistent. The egoist really doesn’t want everyone to be selfish all the time, because ethical egoism, if adopted universally, would lead to undesirable social consequences.
An alternative is to argue that helping others who are likely to reciprocate favours is consistent with ethical egoism.  Incidentally normal people who are not sociopaths would likely lose self respect and become less happy if they only helped others at such times.
Ethical egoism, like all exclusively subjective philosophies, is prone to constant self-contradiction because it supports all individuals' self interests. It also can lead to very unpleasant conclusions, such as choosing not to intervene in a crime against another. Egoists have difficulty judging anything that does not deal with themselves, which is one reason why ethical egoism is so impractical for people who are very aware of the world. The very legitimacy of the theory is often called into question because it prevents its own adherents from taking reasonable stances on major political and social issues and cannot in itself solve these issues.