The fact that Earth ultimately didn't get turned into an uninhabitable wasteland because some characters did the right thing without hesitation when it was absolutely required may restore some of your faith in humanity. Humans aren't quite as bad as their creators.
When Janek decides to sacrifice himself and the ship to save earth, his co-pilots insist on staying behind to help him, because he's "a shit pilot". Their loyalty is pretty heartbreaking.
The way Holloway practically tackles Shaw to comfort her after inadvertently reminding her she can't have children.