Unrealistic Expectations
Back in the day, I had seen this as well when looking for a job. Some of these were pretty bad...for instance requiring 5+ years experience with Windows 2000 back in 2001 or 2002. Now it might be possible, with doing beta testing and such to have this amount of experience, but highly unlikely (or if you worked at MS developing Windows 2000 you might make the cut).
Anyways, I figure that if the company cannot do their job with their expectations, then the company isn't worth my time either.