“Then you'll have to kill me, ogre. I owe that dwarf a debt you can't understand.”
“Love is for children. I owe him a debt.”
“Which reminded me...I still owed the gods a debt."You're a genius," I (Percy) told Annabeth.”
“Worrying is like paying a debt you don't owe.”
“Worry is the interest you pay on a debt you may not owe.”
“And don't tell me debt is not a big deal. Debt will cut off your legs and laugh at you as you grovel in the dirt begging for mercy. If you don't need it, don't get it. If you can't afford it, don't get it. If you're already in debt, get out quickly. If you think you'll never get out, you're right, you won't.”