As a parent, I shouldn't say such things, but here it goes: sometimes you just need to back off and let a teen be a teen.
This does not apply to issues such as borrowing your nice, new German car, or when he or she wants to spend the night at their true love's house. The Chicago Tribune, however, has a good example of when it does apply: when your child gets his or her first job. I realize that the notion of teens working is a strange one in many countries (or continents), but I think there is definite value in it so long as it doesn't interfere with school. This is a great way for kids to develop a sense of responsibility and to get rewarded for their efforts. The Trib article also brings up our role as parents during this time.
While our kids will forever be babies in our eye, there comes a point where it's time for them to grow up and learn to deal with their problems. In workplace conflicts, it's a great chance for them to learn to work with different kinds of people with different personalities and to adapt to them.
Of course, some problems may require a bit of wise adult intervention, such as harassment, but if little Johnny gets an earful for not finishing his project on time, let him deal with the consequences and resist the urge to give his boss a piece of your mind.
This experience is a wonderful introduction to adulthood and the workplace as much as we believe we have all the answers, there are some lessons we can't teach our children and only experience can.