Alignments are hyper-stereotyped to help a character fit into the world of Darkness Incarnate. They can (or can not, depending) define a large portion of your character's actions. Their alignment often dictates how they begin a battle, how they fight during it, and their willingness to 'cheat'. However, as with all alignments, these are just a character's general disposition. Everybody lives in a gray space, since the world in which we live in is gray. Even the most devout paladin is able to lie and cheat when needed, while the most evil and cold assassin can show love and affection for an orphaned child. Think of your allignment more as your character's mood, disposition, and thought pattern. Take your alignment as far as you would like, or pay little attention to it at all. It's all your decision, and few (if any) people will call you out on acting your character's alignment.
If they do, slap them in the face for me.
The three main alignments are:
Good: Those who are aligned more toward the general good. They have a general disposition to be good natured and fair, rather than be underhanded and mean, and are usually law abiding. These characters can be something as simple as a happy child, to a devout paladin, or a lawful brigand. Any character can be good, just like any character can be evil. The degree to which they are good is defined by that character alone, as is their way of being good.
Neutral: The middleground. The gray space. This is where most people live in this world. They have no predisposition, and generally let their morals and emotions flow freely. With no predisposition toward neither law nor chaos, good or evil, they find themselves as some of the more dynamic and surprising people to walk the world, generally they are guided by their free-ranging emotions and whims. A teacher, a jail warden, and a bounty hunter can all easily fit into this category.
Evil: The darker side of life, relatively speaking. These people are the opposite of good, more inclined to lie, steal, cheat, and be underhanded than their counterparts. These characters are more inclined to do whatever they want, whenever they want, however they want to do it, and normally have a sour disposition. Evil characters are more impulsive and rash, but generally get things done in a quicker fashion than the law. A schoolyard bully, a murderous and torturous assassin, or a city guard with a bad attitude.
Remember, whether a thing is good or evil can be based completely upon a character's own views, and not the views of the general public.