It's bratty because it's selfish and self centered. Because Naruto doesn't move on Boruto's schedule, Boruto decides to throw a ***** fit, because he can't get his way.
Selfish and self-centered?
Lmao, no.
Boruto's description clearly stated that he cared about his little sister very much and is always kind to her. Is throwing the cake extreme? Yes. However, Naruto is BARELY around to begin with so him ditching his daughter's birthday to go attend his Hokage duties once again is enough to piss of any child who cares about their younger siblings feelings. The fact that you are trying to reduce him to being selfish and self-centered is laughable because in Gaiden the reason he changed his mind about Sarada delivering the bento was because he thought about Hinata during Sarada's little speech. If Boruto was really self-centered and selfish in the first place then he wouldn't have bothered to even care that Naruto left her birthday or even bother to change his mind about the bento.
So yes, let's call a 12 year old child who misses spending time with their father as bratty selfish and self-centered child because that makes total sense. Yes... sooooo selfish.
It's normal to be bratty at some point of our lives, but its not when the person is a brat 22/7 everyday
If people want to see Boruto as bratty then fine but the reasons are so retarded. I see if the kid started flipping sh-t and was like:
"I'm the Hokage's son so I do whateevaaa I like!"
"My mother is from the famous hyuuuuga so you have nothing on me!"
"Ha, my daddy can get me whatever I want so don't you dare look down on me"
but it's a 12 year old boy who is angry about the lack of attention his family is receiving as if they are the 2nd and Hokage duties is first. I mean.. really? Cmon. I would say he is a jerk but not a brat.