There is absolutely nothing that I know of that is purely one thing.

The reason is, for something to be "Good" there has to be "Bad" to it as well, otherwise you would have no definition of what the "Good" is.

For example, if there were no "Bad" Christians, how would you be able to explain what a "Good" Christian is?

You should do some reading on Lao-Tsu. He was an ancient philosopher that pretty much revolved around this idea. I believe he was the first to come up with the concept of "Yin and Yang."