I know some people prefers to sleep in total darkness and admittedly sometimes one would feel that it gives us a much more restful sleep. However, in Feng Shui sleeping in total darkness is not a very good idea.
Sleeping in total darkness will create total yin energy. While we sometimes need yin energy to avoid from having too much yang energy, being totally yin atmosphere is also bad. I once had an officemate who always feel that he slept soundly with all the light out, but we noticed that he seems to be more prone to minor accidents. When he consulted me, I told him to try putting a night light while he sleeps to simply add a little yang energy and to avoid being in total yin room. Reluctantly, he did it, and surprisingly it worked, the accidents stopped!
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