My Wish Granting System

John Walker an 18 years old guy had a lot of regrets in his life just like every human do. After being pushed off the rooftop, John died with lots of regrets and at his last breathe, he did not wish for a second chance like other people do but he instead wished,
"I wish no one in this world will ever have regrets as I did," Walker's eyes slowly lose light. Everything went dark afterwards.
When he opened his eyes once again, Walker was granted not only a second chance at life but also a wish granting system.
He went around granting people's greatest wishes.
But what if this wish granting system wasn't as easy as it is?
If it was merely granting people's wish life would have been very easy but not when he is one day challenged by the unknowns?
WARNING: This is not your normal system novel that starts with fighting at the beginning chapters. Yes, they will be a lot of fighting scenes but not in every chapter.
This is my first time writing so please support me and don't be too harsh on me since I am a human with feelings.