1. Google will give your keywords a "low quality score" but will not tell why.
2. You can screw for weeks with improving your landing page, keywords and ads all you want, but your quality score still won't move.
3. Google will lower your quality score suddenly and without warning, raising your cost per click 20 times. By the time you figure it out, you will have paid $3.00 for each click you were previously pay .15 cents for
4. Google will "recommend" new keyword "opportunities" for you, but these keywords will register as "low quality" if you add them to your keyword list.
5. Google reps will say they will call you back, but they really won't. They don't care.
6. Google thinks they know more about your business than you do, but they really don't.
If there were another game in town, I would move all of my Adwords business today. Google is acting like an evil monopoly. Google Adword's suck-ass quality can only bode poorly for Google as emerging competitors like Facebook, Bing-Yahoo, Baidu and others begin to get their acts together.
The unfortunate bottom line is that Google doesn't give a shit about serving its small long-tail customers. Now that they're a giant, they could give a shit about the ants that built the pile that is now Google.