"I...Well, I'm a man of extremes, Navani. I discovered that when I was a youth. I've learned, repeatedly, that the only way to control those extremes is to dedicate my life to something. (...) They're the means by which I bind myself. Like the enclosure of a fire, meant to contain and control it."
He took a deep breath. "I'm a weak man, Navani. I really am. If I give myself a few feet of leeway, I burst through all of my prohibitions. (...) If I let a few cracks into that armor, I might return to the man I once was. A man I never want to be again."
"You are not a weak man, Dalinar," Navani said.
"I am. But weakness can imitate strength if bound properly, just as cowardice can imitate heroism if given nowhere to flee."
The Way of Kings, by Brandon Sanderson