I don't know why, but inventors LOVE to focus on the background section of patent applications. And most of the times when they answer my questions about their invention, it almost comes across as a sales pitch. People really say stuff like:
"This innovative product..."
"This is revolutionary because..."
"Nothing like this has ever existed in the market..."
"Isn't this the best idea, like, ever???"
"This reduces the cost of..."
And my response is always the same: "Hey, you don't have to convince me, I just need to know if you've told me everything about your invention and that everything you're telling me is accurate and to the best of your knowledge."
The thing is, patent examiners don't really care how good your sales pitch is. Your sales pitch may be important when it comes time to sell your product, but that's not really the case for getting your patent application registered. Sure, it is important that your invention is innovative. But the best way to convey that your invention is innovative is to make sure that you discuss every feature of your invention in detail. This way, people who are reading your patent can understand what the innovative feature of your invention is.
There are ways though, to highlight why your invention is better without making it sound gimmicky. You can add a prior art section in your spec and compare your invention to existing prior art inventions. Also, I usually say stuff like, "____ increases convenience to the user by ____."
I like using this type of language because it makes me sound more like a lawyer and less like a sales person. IP Watchdog touched on this topic also. The point is, there is a right way and a wrong way to describe your invention. And when you're writing a patent application, you have to sound more like an inventor and less like a marketing person.