All this growth and development uses a lot of energy, and this may be why teenagers often seem to need so much sleep. Their getting-up late may be irritating, but it may well not be just laziness. As well as growing taller, starting to shave or having periods, people of this age start to think and feel differently. They start to make close relationships outside the family, with friends of their own age. Relationships within the family also change.
Parents become less all-important in their children's eyes as life outside the family develops.
Real disagreements emerge for the first time as young people develop views of their own that are often not shared by their parents. As everybody knows, adolescents spend a lot of time in each other's company, or on the telephone to each other. Although this can be irritating to parents, it is an important way of gaining a sense of identity that is distinct from that of the family. These friendships are part of learning how to get on with other people. Clothes and appearance become very important, both as a way of expressing solidarity with friends, and as a way of declaring a growing independence from the family.