In theory people are either morning people, who get up very early, or afternoon people, who don't, but things may not be quite as simple as this. People who sleep until late may not do this on purpose. They may just be under the impression that they are afternoon people, so they simply couldn't get up early even if they tried. Or they think that they could get up early, but they are out of practice. It's just a question of getting used to it. Then one day they realize that morning people are more successful. They decide they have to change, but then their problems start. For example, you may really want to get up at 5.00 am, but when the alarm clock goes off, you decide that perhaps you are an afternoon person after all. And so you fall asleep again.
What can you do?
Some research suggests that people who want to get up early often go to bed too early, and this is what lands them in trouble when the alarm clock rings. Their sleep patterns are out of control, and either they can't get to sleep or they wake up too early, or they can't wake up until late. In, fact we may not need the same number of hours sleep every night. As long as we sleep roughly the same amount on average over a period of time, we probably get enough sleep. So in the end we may be better off going to sleep only when we really feel tired, provided we always get up at a fixed time each day.