11. The Truth: (Noun) This is possibly the most important concept in this list. Truth is often mistaken for religioun, philosophy, or principles. This, of course, is incorrect.
Truth is, in the plainest terms, the way things really are, as opposed to the way we'd like things to be. The truth can change with conditions (ie, it's true that the sky is clear here today, but that may not be true tomorrow), or even with perspective (a simple lesson in relativity will demonstrate that), but it is not subject to opinion or wishful thinking or even the strident demands of those in authority.
Needless to say, telling the truth will not make you popular at parties, because most peoples' most closely held beliefs are not based on truth. In fact, there isn't a single political philosophy that is based on truth, nor any religions (at least, not that can be proven). Communism doesn't work, no matter how badly you want it to. Neither does laissez faire capitalism, anarchy, or anything else that deviates from the primate pack mentality (Constitutional monarchy does just fine, as does a democracy/republic so long as there is a president/prime minister/whatever to represent the alpha of the pack). The reason for this is that the truth is that we are primates, and we act like primates, so - at least in a group of any size - we need alphas, and the rules that they enforce.
Sometimes it's not always desirable to TELL the truth ("My, what an ugly bride"), but it is always desirable to see and understand it, unless you're the kind of person who likes walking around cacti with a blindfold on.
In short, the truth is the way things are, whether or not you like it or care to see it. You can often get away with ignoring it, but eventually, you're gonna get bit.
The truth is a horrible thing. It isn't always noble, it's rarely pleasing, and it can sometimes even drive you mad. But it is the only thing worth having.