One criticism I could imagine being brought against Libertarianism is that it caters to the "Selfish", especially since Ayn Rand created her philosophy of selfishness. However, it seems like she grouped "self-interest" into "selfishness". The difference is that all human motivation arises out of self-interest, while "Selfishness" excludes the self-interest of others. Therefore, someone could act altruistically through self-interest. Most Libertarian ideals aim to reduce the power of government down to national defense and a few other light, anti-monopolizing interventions to let the self-interest of the people flourish. Therefore, it is a very unselfish political idea. Philanthropy is often one of those self-interests. The social justice fantasized by liberals could be had under libertarianism, but only if it is guided by the citizen and not the government.
The philosophy of Libertarianism asserts that free-will exists and that everything follows thereafter. Interestingly, though, the political libertarianism has a passively deterministic mechanic.
Envy in moderation is healthy. However, the envy of consumerism consumes the self-interest of the consumer. The consumerist is envious not because he has determined what he wants, but because he is told that he should have something.