Many users here do not seem to understand people very well. Thus I have written this essay to hopefully enlighten some.
The first thing to understand is that people will do what they want. People only edit Wikipedia (vandalism or otherwise) because they want to. For them, the incentives for doing so are greater than the disincentives. With a few exceptions, people edit Wikipedia in their spare time, making it simply a hobby.
What sort of edits they make depends largely on their understanding of Wikipedia. People who view Wikipedia as an "encyclopedia anyone can edit" are likely to make a test edit to see if it is really true. People who see Wikipedia as a large billboard that is read by millions of people each day are likely to add attention getting or self-promoting edits (not necessarily vandalism, but usually vandalism or advertising of some sort). People who understand Wikipedia to be the world's largest encyclopedia are likely to contribute positively to it. People who view Wikipedia as a stressful dramatic project with several detractors are likely to get burned-out and stop editing. As people edit Wikipedia, their understanding of it changes. For me, this is the reason for WP:AGF, assuming good faith allows new users to view Wikipedia as a legitimate encyclopedia, and prevents experienced editors from getting burned out. I believe that explaining to vandals the purpose of Wikipedia to increase their understanding will prevent future vandalism from them more than a block will.
Secondly, anonymity makes people act like jerks. Without the normal social pressures inflicted on people to keep up their reputation, people tend to act more snappish, with a shorter temper than they would have to an equivalent situation in normal life. Luckily we have pseudonymity to keep some semblance of this normal pressure, encouraging users to build a reputation. But the important thing is to not take any of this jerkish behavior personally. Since nobody, with a few exceptions perhaps, actually knows you, there is no reason to take offense for rude behavior. At the same time, it is your responsibility to consciously strive to be exceptionally nice to everyone, even if you disagree. A good rule of thumb is: the more you disagree with someone, the more respectful you should act towards them. Remember, the dispute should be about content and not the person. This way, much less drama should ensue.
To summarize, people edit Wikipedia according to their understanding of it, and disputes should be about content not people.
Thank you for reading. Feel free to comment on anything on my talk page. Jkasd