It is only Allah whose discretion holds supreme in this world. No one else's discretion has in reality even a trace of authority. However, for the sake of trial, Allah has sanctioned freedom to man, who has been given considerable liberty in an otherwise completely enslaved existence to see how he uses it: does he opt for the realistic choice of submitting to Allah's -- the real Master's -- will or does he get carried away by the thrills of his undeserving liberty and, as a consequence, resort to a rebellious attitude.
Allah has prepared Paradise for those who despite possessing many options choose to remain optionless; those who volunteer to fear Allah even on occasions when fear is not seemingly warranted; those who, despite wielding full authority, surrender all their authority to Allah.
When such people are provided with sustenance through the medium of some apparent material source, they acknowledge that it is in fact Allah Who has arranged it for them. They have the liberty to be unfair to others, but they check the sinful inclinations of their liberty for fear of Allah. Opportunities of demonstrating anger, hatred, and revenge come their way, but they choose to exercise restraint on occasions of anger and offer forgiveness on occasions of hatred and revenge. Allah allows them to be praised lavishly by others, but they find solace in remaining humble. Allah makes them wealthy, but instead of spending their wealth to satisfy their vain desires, they find it more satisfying to spend their wealth in His way. They follow the way of Allah instead of following the way of their own whims; instead of living for their own sake, they live for the sake of Allah.
The serene world of Paradise is indeed for such people. They make themselves subservient to Allah with their own free will; they choose to remain constrained within the divinely ordained restrictions, despite enjoying the freedom to remain unrestricted.