I've been thinking for a long time, my friend Serenus, about how to describe this state of mind. The best comparison I can find is people who have just recovered from a serious, long illness. Even though they're better, they still feel occasional aches and pains. They've beaten the disease, but they're still suspicious it might come back. They're perfectly healthy, yet they keep asking the doctor to check their pulse. Every time they feel a little warm, they worry the fever is returning. These people aren't sick, Serenus — they're just not used to being well. It's like a calm sea or lake that still has gentle ripples even after a storm has passed.
I have long been silently asking myself, my friend Serenus, to what I should liken such a condition of mind, and I find that nothing more closely resembles it than the conduct of those who, after having recovered from a long and serious illness, occasionally experience slight touches and twinges, and, although they have passed through the final stages of the disease, yet have suspicions that it has not left them, and though in perfect health yet hold out their pulse to be felt by the physician, and whenever they feel warm suspect that the fever is returning. Such men, Serenus, are not unhealthy, but they are not accustomed to being healthy; just as even a quiet sea or lake nevertheless displays a certain amount of ripple when its waters are subsiding after a storm.