Sometimes they are supercharged, other times listless and moody; sometimes full of ideals, other times totally self-centred.
Suddenly your 'great kid' has become a demanding even disruptive family member who seems to want to challenge authority at every turn and rebel against longstanding family rules and practices.
Being seen with their parents in public can be 'uncool', while their newly emergent sexuality can make them seem like strangers. And of course, they consider themselves bullet-proof as they engage in all sorts of risky behaviour.
The teenage years, in short, can be an exasperating and worrying time for the parent. But not always. Teenagers can also be fun, loyal, and caring family members and friends.
They're full of optimism, idealism and energy and can be great companions. Seeing the world through their eyes can be really energising for you too. So don't focus on the wild behaviour, the moodiness or the rebelliousness. Instead see it as the growth of self-confidence and assertiveness.
Every adolescent is different and while some have given the age group a bad name, others cause their parents no problems at all. So relate to your teen as an individual, don't typecast them, focus on their good points, be loving, patient and supportive.
Take the time to chat with them in a mature way recognising the adult they are becoming. Listen to their ideas and respect them - even when they are opposing your most dear beliefs. After all challenging authority is a part of growing into adulthood.