creation - How the idea of "the bread of shame" aligns with free will

Jewish thinkers^(Who?) sum up G-d's creation of the world as follows: It was the ultimate act of goodness. G-d is perfect and infinite. He has no need for a universe; He has nothing to gain from creating mankind. Thus, we can only view creation as an act of altruism -- for the sake of man.

Further, if G-d is truly perfect, His acts must be viewed as acts of perfect goodness. G-d created man in order to have creatures upon whom He could bestow goodness. Creation was, therefore, the ultimate selfless act: A G-d who needs nothing created a world in order to give the man everything.

But Instead of giving us everything on a silver plate, the human being has to work for it. My question is: Why?

Zohar and kabbalists and the Ramchal refer^(Where?) to the "the bread of shame principle" ("nahama d'kisufa"): If G-d were to "reward" us for doing nothing it would not be a reward; it would be humiliation/shameful.

How does this principle work and how it leads to having a free will?^{(Is this a separate question?)}