I've noticed this in not only my current project but previous projects that I've worked on. When we're looking for someone to help do some specific programming tasks we tend to have a problem with people not really being polite in their applications. They treat it as though they did it as more of an afterthought. I don't seem to see this problem in artistic positions...
I mean, you need to convince the person that is reviewing your application that you are somehow extra special. I find it hard to understand how you'll do that by being arrogant and rude.