Taxes are critical to the safety of the individuals in society. They provide a mechanism for policing and defense, without which anarchy or invasion would occur immediately, followed by slavery.
The irony is that we must take money by force to stop others doing so. Taxes are in fact little different to racket protection money. Though in a democracy they are hopefully agreed to by the majority.
A slave is someone who has their freedom taken away. We initiate force against those who do not pay their taxes - in a sense we make them slaves. We make ourselves slaves to ensure our freedom. Freedom is slavery.
Taxes are also a mechanism for common infrastructure to be paid for. Much of what we think of should be part of the common wealth could in fact be administered more efficiently by private industry. However we are emotionally attached to the notion that 'roads, schools and hospitals' must be paid for from our taxes, and we cling to the quaint, but naive, notion that this is where most of our taxes go.
Taxes are also a good way for the lazy in society to force the hard working to give them money via wealth redistribution. By using a steep 'progressive' tax rate, those with less money can effectively milk those with more money, without having to work for it. This can be used to implement a democratic form of semi-socialism, in which the rich do not have all of their wealth redistributed to the poor, but only most of it, which we see realized as subsidies and welfare payments, and pork barreling.
While redistributing of wealth may seem to be an effective utility maximizing tool, it provides a disincentive to earning, and therefore creating more wealth.
If everyone's earnings are placed into common wealth, and everyone earns the same amount regardless of how much they produce, no one will bother producing anything - an extreme of tragedy of the commons (communism). However if people are only allowed to keep half of what they earn, they will only bother earning if it is very easy. The higher the marginal tax rate, the sooner people will stop working, and the less wealth will be produced.
Further, poorly designed welfare systems create traps in which the effective marginal tax rate is so high, that it is not worthwhile to work more. In some cases the marginal rate is greater than 100%, so people actually get less income if they produce more wealth.
Taxation is taken from people by force, and therefore is of questionable morality. There are some who believe that all taxation is immoral because it is taking money by force, others believe that all wealth should be taken from people and allocated by the government.
A list of possible taxes in order of controversy follows: