I think it's also one of the reasons people have a hard time with
seo and think it doesn't work. The basic ideas and concepts of
seo are pretty easy to grasp. Understanding that links are important doesn't take a lot to see. The problem comes if you don't want to look deeper. Sure links are important, but not all links are equal.
In general the links that are easiest to get are the ones that count the least. That's very generalized of course. Some would rather not hear that since the implication is you have to work harder to get the links that will help you more.