“So the pleasure system,” Windy was saying, “is modulated by neurotransmitters called opioids. They help us enjoy the good things in our lives and tune out discomfort. But the system of desire is governed by dopamine, which makes you antsy and itchy with longing.” “So they kind of cancel each other out,” Jake said, following her thinking closely. “That’s right. When desire is high, pleasure and satisfaction are low. They’re, like, at opposite ends of a seesaw.”