" The first step is to care, Tukks’s voice seemed to whisper. Some talk about being emotionless in battle. Well, I suppose it’s important to keep your head. But I hate that feeling of killing while calm and cold. I’ve seen that those who care fight harder, longer, and better than those who don’t. It’s the difference between mercenaries and real soldiers.
It’s the difference between fighting to defend your homeland and fighting on foreign soil.
It’s good to care when you fight, so long as you don’t let it consume you. Don’t try to stop yourself from feeling. You’ll hate who you become. "

― Brandon Sanderson , The Way of Kings (The Stormlight Archive, #1)