does not like to sleep

It is almost ten at night here now and my son just went to bed. He is supposed to be in bed at nine, but sometimes he does a lot of things and forgets the time. I have to keep reminding him about his bed time. He knows already how to check the time, but he does not care about it. He does not like to go to bed and sleep. I do not know why a child does not like to sleep. I wish I am still a child so that I can have enough hours to sleep.