It's a common misunderstanding that cats are nocturnal. They aren't. By nature, they're crepuscular. In other words, they normally are most active on the borders between night and day.
Cats need to sleep more than people do, and domesticated cats are most likely to do so when there are the fewest interesting things going on. Cats have active minds and are always seeking something interesting to see, smell and do. Their sense of safety is largely oriented around knowing what's in their environment in detail. Change something around, and a healthy cat will check it out immediately. An inborn spirit of playfulness makes them fun to be around.
In watching most domestic cats, I see them as being bored with their environment, not played with or given interesting things to explore and do. Cats will sleep out of sheer boredom, too.