sleeping when it's cold: deepest peace imaginable, opportunity to bury yourself in blankets and indulge in the ancient mammalian instinct to curl up and sleep somewhere warm and dark and enclosed, instant and dreamless rest
sleeping when it's even slightly warm: torturous, only options are kicking off blankets and feeling horribly exposed or laying in your own sweat, impossible to get comfortable, exhausting and demoralizing sisyphean task