If you've lost your faith in humanity because of something that happened in Game of Thrones, then the best and simplest way to restore it would be to go outside, look around, talk to people and interact with humanity until it dawns on you that Game of Thrones isn't real life, and real humanity doesn't abide by what happens in Game of Thrones.
There you go, instant faith in humanity restoration, and it probably won't take more effort than walking to the end of your street.
However, in the future if you want to avoid other existential crises, then I suggest you don't use works of violent fantasy fiction as the measuring stick for humanity... in fact, it'll probably be best not to let any works of fiction dictate you mood and your faith in humanity, positive or negative (as it could be just as disastrous the other way if you watch some happy feel-good cartoon and then go skipping through a crack slum at night singing 'Zippity Doo Dah').