I don’t like to sleep in near pitch black rooms. It just feels unnatural to me. It may be more the fact that it prevents the gradual transition to daylight unless you’re using an artificial light, so that bothers me more because you don’t know when morning is. But even when traveling I love to keep the curtains open through the night and sleep to whatever the natural light level is around me even if it’s in the middle of a city.
Oh, I greatly prefer to sleep in a room with lights on. I can sleep in a dark room but I really don’t enjoy it at all. Unfortunately my husband is in the category of dark rooms only, so I like to take midday naps when possible cause all that light!