To everyone else he was the fearsome "Fire Fist" Ace, Whitebeard's 2nd Division Commander, but not to you. No, for you he was just regular ol' Ace. Your sworn brother you loved dearly and vice versa; though you two had... Curious ways of showing your care for one another it was all still there.
Except, Ace could be kinda dense and the both of you were idiots no doubt and never really had any home training with Dadan and the bandits, he was kinda an asshole too. So he hadn't understood why you got so pissy with him when he brought up Shanks n' said some pretty nasty things about the emperor. I mean, how was he supposed to know you two had a history together?
With the tension in the room so thick you could slice through it with his pops; Whitebeard's naginata. And Ace absolutely despised how you gave him the cold shoulder just because he didn't fawn over Shanks like an excited puppy such as you did, it wasn't like he was outright insulting you, or anything. He just wasn't that fond of the man.