This is one that I have thought about for a long time and haven't seen anyone do and it just doesn't make sense to me as I think it is a great idea for a novel and I doubt I am the only one that thinks that as well.
This is literally such a broad topic cause it could actually be anything that you could ever possibly think of. I didn't think much into a scene for this one because there is no need to. You could literally close your eyes and ask yourself what would you do if you had gotten the chance to have 3 wishes and BAM! you got an idea for a novel. I mean you could ask yourself about why the Main Character has the chance to have 3 wishes, but the majority of Novels don't explain the reason MC just magically has treasures and abilities falling into his lap and teachers trying to flock to him with people flocking to him to try to kill him. If you want to give an explanation on why the MC magically gets 3 wishes, I will give you one I can think of off of the top of my head.
The setting is modern day Earth, not futuristic, not in the past or on a different planet or realm, just present day Earth. He lives alone with his mother and father as an only child. His father used to serve in the military, but was shot in the back while on duty and is now confined to a wheelchair with his wife to look after him and make money doing odd jobs. The son, our MC, is walking home with his mother from the grocery store, as they didn't have enough money for a car, when he hears honking behind him and then darkness as him and his mother get hit.
Later he wakes up in the hospital and finds out he was a victim of a hit and run. He asks about his mother only to find that she is seriously injured as the years of hard work had weakened her greatly. He hurries to get up and see his mother and the doctors did not stop him. When he got to his mother's room he saw her weak and frail, with an oxygen mask on her. He hurries to ask about how she is, when she interrupts him and starts telling a story of her own. She said that she was once from a prosperous family and was the young miss of said family. She told about how the family was peaceful and never bothered anyone but was definitely well-off. She tells how in her house there was a legend about how the family heirloom was actually an artifact that had the devil sealed inside it. The reason there was a legend like this was because it was said when you were around the heirloom, you could hear the whispers of the devil enticing you to say what you want and makes you feel dissatisfied with how you are and that you could be so much better than what you were. Of course those were just made up stories, as no one had ever confirmed the existence of such whispers, but none the less the heirloom was very well guarded and was sealed in a bullet-proof glass case.
However, one day that family ceased to exist. Apparently, one of the younger members of the family were hanging out with other young people from rich and powerful families and got drunk and told the others about the treasure and said it could give you anything you want. Obviously these were just a drunk man's ramblings, nothing to be taken serious, but the other young people believed him and hired people to slaughter the family for the treasure. However, the Main Character's mother escaped with a fake identity and the treasure and has been hiding away ever since, but now the mother was passing down the treasure to him. After she passed the treasure to him, her heart monitor started beeping rapidly, until it flat-lined. She was gone, without her husband to see her final moments.
Months passed and the MC is going to school. Disheartened by his mother's death, his grades drop from the former A's and B's to C's, B's, and D's. Seeing this as a chance to mess with the MC, a group of people started to bully him everyday, but the MC persevered and gradually brought his grades up to an A because that's what his mother would want. On his way out of the school, to the job he had to take up, as he was the only available member of his family to work, he was stopped by the bullies beaten up. With scrapes and bruises all over himself, he couldn't go to work, so he went home and took a shower after calling in sick. When he took his clothes, he saw the artifact, which I will say is a ring, on a string around his neck, was covered in blood. Seeing that, he washed the ring and scrubbed it as hard as he could, when he felt it getting hotter and hotter. Suddenly, smoke started shooting out of the ring and gradually coagulated into a humanoid shape.
What was left after the smoke dissipated, left the MC in shock. What was there was a man who had odd features, his skin was grayish purple, he had long black hair and neatly trimmed beard, he had 2 golden hoop earrings on each ear, wearing an expensive looking suit with a red tie, and had a mischievous smirk with a twinkle in his golden eyes. He asked the MC that he was a legendary genie and that he could grant the MC 3 wishes of his choice and would tell him the price for each wish. The MC was obviously shocked at this, but soon calmed down and asked if he could put clothes on, which the genie seemed somewhat embarrassed as he agreed.
Coming back into the bathroom, he saw the genie standing there with the twinkle back in his eyes. He told the young man he could give him whatever he wants as long as he pays the price for it. Thinking long and hard about this, the Main Character said ...
This is just an idea of how to introduce the 3 wishes but here are some 2 wishes ideas that could be used in a novel:
* Wishing for all existence to have a level system (all existence is important because in case the MC goes to another realm or world) from there on out, with level befitting there strength; wishing for all fictional worlds to exist; wishing for the ability for full control of space and time
* (If MC is on a world where Mana, Qi, Body Refinement, Etc. is a thing) wishing for himself to have a level system with no level cap, that can evolve; wishing to be able to create any skill he wants by thinking about it, like Swordsmanship Mastery, Close Combat Mastery, or even Exercise/Training mastery to get the most out of everything he does; wishing to get stronger whenever he sleeps
* (If MC in cultivation world) wishing for when he kills someone he can absorb their strength (Qi, Body Strength, Soul Power); wishing to become extremely talented in everything, from combat to alchemy (so he can kill enemies easier and make money); wishing to be able to change himself in any way possible (disguise himself from enemies or give himself animal attributes like scales or claws to fight with)
These are just some ideas that I think would be pretty cool as a novel idea.