Well, nothing is that simple, in fact one of the biggest problems in society is that each of us has their own biological clock, with preferred activity and sleep hours, yet we are forced to align our schedules to the same universal standard. Of course, it is absolutely vital for the way our current society functions (because we, as a society, work together, take classes together, commute together, socialise together, celebrate together, and so on), but it definitely has been hurting billions of people for the past thousands of years and we should look for a way to eliminate this system as soon as possible.