Most people would admit that there are certain traits which it is morally good to possess. These are known as virtues, and it is easy enough for any sensible person to recognize them - courage, justice, friendliness, honesty, ect. These are offset by vices - bad or immoral traits such as cowardice, unfairness, rudeness or treachery.
It is also clear that there is some relationship between the vices and the virtues, and lay out various schemes for how they are all related. One intuitive idea is that vices and virtues come in pairs, and refer to the same quality, that for each quality there is a spectrum, with the virtue at one end and the vice at the other. For example, they would say there is a continuum of bravery, with the very brave on one end, and the very cowardly on the other, and the closer one could come to the brave end, the better and the more perfectly they possess the virtue.
A fault with this is that it is quite possible to possess too much of a virtue, to the point where it becomes a negative attribute rather than a positive one. Therefore, Aristotle advances another idea, that virtue is defined as the point of balance in a continuum with vices at both ends. In this system, rather than having a simple scale between bravery and cowardice, Aristotle sees the virtue of bravery as the balance between the vices of cowardice and foolhardiness.
However, both these systems seem to fall short of representing one very important facet of human virtue - that virtues that bear some sort of exclusionary relationship with one another. For example, prudence and bravery, generosity and financial responsibility, mercy and justice, loyalty and impartiality, or innocence and cunning. How is one to choose a virtuous lifestyle when faced with contradictory virtues.
An obvious answer, inspired by Aristotle, would be that the key is moderation. One could even be led to believe that each virtue is the same as a vice when unmoderated by another vice/virtue.
The problem with this is that it seems as if it could, very easily, lead to stagnation and mundanity. If everyone ought, with every virtue, to aim for a specific point of moderation, then it would seem to eliminate individuality - if everyone tried to be equally witty, equally phlegmatic, equally equanimous, it seems to me that the world would be a pretty boring place.
Furthermore, it seems wrong to state that every virtue should be moderated. Virtues, by definition, are good, and it is counterintuitive to say that they are good only when moderated by their opposite. But I want to believe that courage IS good, that prudence IS good, and good even when taken by themselves. I want to be able to respect both the soldier who boldly charges under murderous fire, and the prudent general who stays in the bunker, without chiding either of them for their immoderation.
There is a paradox about these contradictory virtues, a way in which they are in constant tension with each other, and yet still complimentary. Neither would be what they are without the other, and yet, unlike the moderation approach, they do not weaken each other either. They remain strong, and because of the dynamic play between them there is far more room for variety - indeed, it is only by such an interpretation of virtue that there can be variety among the virtuous.
Thus, I am free to support many varied views, and recognize the goodness of them, and apply that goodness to my life, without emasculating them. I salute both the optimist and the realist, and give a nod of approval to both the demure and the flamboyant. I am free to endorse the need for tolerance and acceptance in society, but also to stand up and make rugged, solid claims. And life is far more interesting, this way.