I noticed that we never see Neteyam hiss (Kiri too if I'm not mistaken but I wanna focus on Neteyam) Hissing is an expression of anger and we always see Neteyam holding back. He has to be calm, collected and a good son/big brother.
But do you know what I want? When he comes back (don't fight me on this - he has to) I want him to go feral because I know he has his mother's rage. And I want him to kill Quaritch just like his mother did before him. I just need him to blow up. It will be spectacular.
So will Lo'ak's blow up when he finds out Spider saved Quaritch.