A comfortable night's sleep refers to getting a good quality and restful sleep, where one feels relaxed and refreshed upon waking up. It means being able to fall asleep easily, staying asleep throughout the night without any disruptions or disturbances, and feeling well-rested in the morning. Factors such as temperature, mattress comfort, pillow support, noise levels, light exposure, and stress can all impact how comfortable a person's sleep is. A comfortable night's sleep is essential for overall physical and mental health, and it helps improve one's mood, energy level, and cognitive function throughout the day.