Why people fail with Google AdSense?

I have many friends who have been involving with Google AdSense and many of them are failing. Why? Because to become successful with adsense you need some sites that generate huge amount of traffic. While advertising my site, I found this is not a matter of a night; you need many of months to come in that position where you will get thousands of dollars per month from adsense. But I guaranteed 98% of you will fail, because you are just desperate to earn money online and you will start exchanging clicks and you will caught. You will be banned and fail every time. I can tell this because I found many of my friends did the same thing and getting banned. Whether there is an exact reason or not if Google find anything wrong they will ban you without any notice. The reason is You Are a Free Member or Publisher of Google AdSense and they have the full authority to ban you at any place at any time. Sometime they make mistakes, sometime you do, does not differ, every time you get the punishment. Why they ban you? They just mention in their mail that they ban you to protect the interests of their advertisers. To them their advertisers get priority, because the advertisers pay them. I just want to say that nothing is Free in life. When you are getting something free, you will be discriminated today or some other days for sure.