The egoist says, “I do what I want.”
The vile egoist (the asshole) says, “I do what I want—fuck the rest.”
The enlightened egoist (the sage) says, “I do what I want, and that will be good for the rest, too.”
As an asshole, your unbridled freedom may give you a certain appeal and bring you some success, particularly in the short term. But being stuck in a combative zero-sum mindset limits your potential, because making other people worse off poisons your relationships, and if you gain pleasure from their loss, you sicken your mind.
As a sage, you think win-win and consider the long-term consequences of your actions: the healthy relationships to be built and the mutual benefits of effective cooperation. Even in the here and now you will profit, namely from the emotional bonus of prosociality, the immediate pleasure of being useful to others.
Alas, there are two serious pitfalls for the enlightened egoist.
First, your attitude of wanting to serve others could stem from an unhealthy need to serve. That’s when “I do what I want, and that will be good for others, too” really means “I do what others want, and I rationalize to myself that this is good for me, too.”1 Such an attitude is not egoism, but servitude, which brings along a loss of respect because it encourages others to take advantage of you.
Second, your aim for cooperation may reveal itself as a conditional good you do only in order to get something back later. If you do something for me just because you expect a favor in return, then you are not really doing what you want; you are doing what (you think) I want and you thereby compromise your true will. You might really want what you expect to get from me (or perhaps money from your employer, affection from your partner, recognition from your peers), but if this expectation makes you do something you do not want to do, you are not free.
You can prevent both these types of servitude by knowing what you truly want to do and acting accordingly. What it requires is that you value doing and being over getting. Sometimes it may not seem ideal to value what you do and are over what you get, but if you relentlessly focus on your actions and state of being first, you will always get the most important things anyway—to wit, freedom and character.