Abaddon's Gate (Expanse, #3)

by James S.A. Corey

That humans only have so much emotional energy. No matter how intense the situation, or how powerful the feelings, it was impossible to maintain a heightened emotional state forever. Eventually you’d just get tired and want it to end.

Show a human a closed door, and no matter how many open doors she finds, she’ll be haunted by what might be behind it.