To anyone working in a software company. My computer is my own. You do not make assumptions as to how I want to use my computer, nor do you make assumptions as to how much I want to use your product, just because I happen to be installing it.
The worse culprits in this kind of thing are probably Real. Real seem to have an entire marketing strategy focused on annoying the fuck out of their users until said users refuse to ever install a Real product again. I know that's the state I'm at, and so are quite a few of my friends. When there's a site that says “requires Real Player”, my reaction is “Oh well, I can't hear that”.