A whole bunch of the games 'secret scenes' have very precise times that you can see them and it's entirely possible to miss. Like Yoruichi's one can only be unlocked during the Yoruichi 2 quest. if you miss it then you cannot see it until your next playthrough.
If you did not buy the snacks after hinata gave you 'grocery money' and you had the few extra dollars you found in the street, (and after that you have to say certain things to Himawari to set up the event happening) .. You don't get the scene just for getting snacks normally during the game.
I suggest you go to the discord and get the guide. it lays out step by step how to get the quest and it is ONLY possible to set it up on day 1, and on day 2 give her the snacks you had bought to trigger it.
Thanks for your answers. But I still don't understand anything! I can't do this damn quest! It's ridiculous. When you first start the game, Hinata wants something from the grocery store and you have enough money. Then Himawari wants snacks, but you don't have enough money for that. I'm talking about the very beginning of the game. Is that the place you're referring to? Did I miss this quest then?
Yes. if you had stood in the rain as soon as the game started, Boruto would have found like $7, which is enough to afford the snacks for Himawari on day 1. and if you did not do so then, you miss that scene. You cannot make it up later and just buy snacks any old time. You had to buy those snacks then... think of it like. there was a super special limited edition snack in the store then, and you missed your chance to buy it because it wasn't there later.
Just to see that one scene. But you have to play the game again in both love and hate routes to see all the games content. You can just make sure you get it on that play-through to unlock it.
I suggest you join the discord or go to the website in order to get the guides. it'll walk you through step by step the beginning of the game to get the Himawari fly incident scene.
Yoruichi has one 'secret scene' too that can only be unlocked during one of her quests and is possible to miss.