What Stops Businesses From Getting Results With Seo?

More and more businesses are ready to engage a pro to do SEO, but some fall off some where. From what I can gather it seems to be these types of issues:
* My SEO provider sucks and I’m stuck in a contract
* Marketing budget has run out
* Fear of trying something new
* Ignorance

What issues do you run into and how do you deal with them?