Do you know who tricks you most easily?

Answer: yourself. 

True story. I bought something. It wasn't cheap. I tried to use it. It didn't give me what I expected. After some time, I realised I had been conned. I was angry with the seller for the false advertising. Does this sound familiar? 

If I examine my experience honestly, the seller had never guaranteed any results or misrepresented any facts. In truth, I had bought it because I desperately wanted the dream to be true. I was sold a dream, and I was the one who convinced myself it was true. 

If you've had the same experience as I did, don't blame the salesman. We learn. We get to know ourselves better. And we move on.