James has always been the more emotional of the two or at least the one most willing to show those emotions. Sirius is tough and manly and guys don't cry and tell each other they love one another. And sometimes when he looks at James and wants to say I fucking love you thank you thank you you're the best fucking thing that ever happened to me but he doesn't because he isn't supposed to but James just knows anyway because he is a fucking telepathic mind reader or something and fuck he can read Sirius like a book.