I usually sleep at 3A.M i prefer working until late in the night and wake up late. But sometimes it depends with the work i am doing, especially working online you have to sleep late in the night because of the time differences with other countries where your clients are from. I like working at night because the environment is very cool and quiet and therefore you are able to concentrate on what you are doing more than in a noise environment.
Also during the day you have so many house chores to do, probably the kids are there and they need your attention, you need to cook for them, they need you to help them in their homework so you find that you have very minimal time to even do your own activities that is why i prefer sleeping late into the night to do my own activities.