You might be surprised to know that according to the theory of the worst offenders in the stress category, it is the "daily hassles" rather than a major life crisis that causes one to feel the most stressed on any given day. Traffic, being late, pop quizzes, demanding bosses, irritating teens, irritating parents, lines at the supermarket, no parking spaces, speeding tickets, parking tickets, dirty laundry, over scheduled, being rushed, etc, etc, etc. I am sure that you and your teens can build on this list forever. It's not that the big things like report cards, college stuff, financial difficulties, family illness or crisis, marriage and partner issues don't cause us stress, that would be a ridiculous thing to say, but it is the smaller stuff that happens on a daily basis that makes us the most crazy.
The good news is that there is an anecdote to these daily hassles. It is called "uplifts." An uplift is an unexpected pleasant surprise (for me, after a crummy day of hassles, it is stopping by my favorite frozen yogurt store for my fix and finding out that Black Raspberry is the flavor of the day. Honestly that changes everything for me.) Or, an uplift can be something that you know will change the course of your day, and availing yourself of it.
Uplifts can be powerful stuff in the stress relieving department. It can be especially effective to lift your teen out of a particularly bad mood. Two reasons this is important. First, if your teen is in a crummy mood, they will make your life miserable. Just being the supportive, "hey honey, what's wrong" parent usually backfires with a "just leave me alone!" Secondly, it is a good way to teach your teen about managing stress.
So here is how it might work. When you "get" that your teen has had a crappy day, for whatever reason they don't feel like sharing, think about what might be an "uplift" for them and surprise them with it. Maybe it is stepping out to Starbucks at 8:00 PM and bringing them a mochachino latte that you know might put a smile on that face. Or maybe their room is a disaster area, and you surprise them when they get home from an evening practice with a nice cleaned up space. Maybe after a particularly stressful day, you gift them a stay home fake sick day to mellow out and veg. Don't ask what they want, and don't expect anything in return. Those are the rules. The whole point of an uplift, is to give an unexpected "gift" that breaks the negative mood, and then lets them move on.
PS: Do it for yourself too!