It seems that some people have bigger reward then others, so you cant extrapolate your own findings that way.

I don't have problem with addiction at all for example. I even practice dropping the stuff that start to get too much into my life - a coffee, game, weed, an attitude, TV, bread, car, whatever really. To me its not that hard, but to others around me it seems hard enough.

The point is, you are a mass of checmicals, it might very well be impossible for you to do so given your particular setup.