I expect that material possessions is a way of being able to measure the rate of "success." We, as humans, like to be able to see thing in order to believe them, and "stuff" is a visible way to measure.
I'm not sure what you mean by "selfish desires." If something is for your highest good, then it is for my highest good, as we are all interconnected. Intention is important, and I think they even talk about this in the video. To choose to enjoy a pleasing, fun, comfortable lifestyle isn't necessarily selfish. Choosing an impoverished life isn't necessarily selfless, either.
To "gain" at the expense of others isn't loving (nor does it produce a peaceful/joyful feeling inside, which is the best guide one can have....follow the peace/joy). It does not bring me peace/joy to move to Calcutta and devote my life to the poor and neglected. It did bring peace/joy to Mother Theresa. And it does bring me peace/joy to devote my time and resources to street youth, teen parents, and perform random acts of kindness. And since like attracts like, I have people magically appear in my life to provide me various things to support me in this. It's a constant flow, like a canal, kinda. Very cool to observe, actually. And very far from selfish.
Beliefs re: flying, breathing underwater, etc -- I believe that if that is something that you truly and deeply desire, that you have within you the ability to transcend the mass consciousness belief that these things are impossible. Many things that were deemed impossibilities are now very un-extraordinary today. Airplanes, space travel, and so on. And on a more "physical body" note, walking on fire.
This topic really has nothing to do with liver flushing, though, so I'll not engage in this any longer through posts. Feel free to contiue this via email with me.