I think Naruto's anger feeds Kurama and makes it stronger. I know how Kurama used to steal his chakra to make his own consume him. What if, Naruto's anger makes him so angry that he gets a chakra boost of his own and fuses it with Kurama to make Kurama's chakra whole again. It's sort of like an adrenaline boost, but Naruto's anger will only trigger it when he is experiencing serious trauma from something like the death of a comrade. Yeah, I know you all think this thread is utter garbage and doesn't make any sense whatsoever, but hey, it's your opinion.