Marinette storming to the Agreste mansion to convince Gabriel to let his son go to New York isn’t the first time she’s done something like that for Adrien. Back in season 2 when Tikki grabbed the book on miraculous that was hidden in Gabriel’s office from Adrien, his fathered noticed it was missing and punished him. Adrien no longer could go to school. It was only when Marinette decided to return the book knowing the importance of it, back to Gabriel in order for Adrien to be able to go back to school. Adrien never learned that Marinette was the reason why the book suddenly showed up and that she was the reason why he was able to return to class.

Marinette doesn’t do this for recognition. Her intentions are to make Adrien happy even if that means her deeds go unnoticed by him. Even small stuff like his birthday gift which brought him a lot of joy when he thought his father gave it to him. She didn’t want to take that feeling away from him so she let him think it was from Gabriel.

But in the New York special when Gabriel informs Adrien he can go to New York he lets him know that he has Marinette to thank since she was the one who convinced him. Adrien already knows how selfless Marinette is and the lengths she will go through for her friends. And of course he knows Marinette has helped him in the past like in Gorizilla but going against his father is a whole another level. So of course he was absolutely thrilled to be around Marinette because his father told him if it wasn’t for her he wouldn’t’ve let Adrien go to New York.

What she did for Adrien was extremely special to him. He was very bummed out because he just knew he wouldn’t be allowed to go to New York but Marinette made it happen. The impact this gestured cause on their relationship was prevalent with how Adrien was acting on the trip. Adrien’s friendship with Marinette grew only stronger and what Marinette did for Adrien made him feel even more closer to her.

I don’t really know where else to go with this I just needed to say this.