There's a birthday card that makes me laugh out loud: rows and rows of owls sitting uniformly on tree branches. Each owl sits upright except one - it's hanging upside down. "I'm a teenager" is the caption.
Teenagers like to be different. They like to push against their parents. Which is why Tom's mum thought that I, rather than she, might be able to persuade him to see sense and work for his A levels. She assumed that I could make him knuckle down. A few choice phrases, a 'buck your ideas up' conversation and he's sorted. Or is he?
What Tom's mum didn't appreciate was that neither she nor I can make an 18-year-old do something they don't want to. Tom may have to fail. For a parent there is nothing harder.
And what does Tom say? "I don't want to work if my mum nags me."
Teenagers are not always rational. If you suddenly sported the latest fashion in trainers, they'd ditch theirs. Part of growing up is finding out who you are; that usually means being as different from your parents as possible.
Tom understands this more than his mum; she complains that he is always in his room, but not always working. "But I'm a teenager!" he says, "It's what we do. My mum has her work, then when she comes home she puts all her energy into me and my work."
But Tom's mum cannot back off. Well-meaning friends – I have this particular T-shirt - have advised her. She nags Tom from the minute he comes home from school until he goes to bed. She can't bear the thought of him not securing that university place she thinks he should have.
It's about control. As parents we feel that we should be able to steer our children through life, and help them avoid mistakes - especially the same ones we made.
What is the worst that can happen to Tom? That he will fail his A levels. He doesn't need high grades for his chosen course, so the odds are he'll be all right. If not, he can re-take them. Tom is very circumspect: "I could go to college, or find a job or an apprenticeship. I'd do something."
Uni's Not For Me is an online careers development resource providing independent advice for young people considering alternatives to university. It has a strong campaigning voice which seeks to erode the stigma associated with the decision to pursue a non-traditional route. Their website features some amazing success stories of teenagers who didn't go to university.
Will, aged 19, is a music scout for EMI. For many teens it's a dream job. Will explained: "I went into sixth form because it was the easy option. To be honest I just saw it as a new social platform that allowed me to connect with more people who were into music. When I found out all my friends were applying for uni, I panicked and thought I should be doing it as well. My mum went to Oxford and my Dad did a Masters at Sussex, so I was surprised when they actually backed me and said there was no point in me getting all that debt."
Will began working two days a week as an unpaid intern for a small music company and through his constant networking secured an interview with EMI. "They'd been looking for a scout for three years but most applicants were older. I was young - which is where the music scene is at - so I fitted the bill."
Unisnotforme.com offers ideas for anyone not wanting to go down the traditional university route: they offer advice on apprenticeships, degrees by distance learning, developing a small business, networking opportunities and more. Above all, they convey a positive message about choosing a career path that does not include university.
And teenagers mature at different rates. As well as the 'summer babies' - those born at the end of August who can be a year younger than their peers- there are others who are still at that rebellious stage when they are doing A levels.
If teenagers are living with a step parent this can make matters worse. How many step parents have heard the line; "You can't make me do my homework: you aren't my real dad (or mum)."
Isn't your relationship the most important thing to preserve? It is, according to Liz whose only son is now at university. Liz and her ex-husband both have higher degrees. Their expectations were that their son would go to university. But Liz also realised the importance of her relationship with her son.
"I realised that my relationship with my son was the most important thing of all. Was it worth nagging him about his revision if all it did was drive us apart? Life was already hard for me as a single parent, often in conflict with his father. The moment I said he didn't have to go to university if he didn't want to was the moment he began to work."
So can you take your hands off the wheel and let your teenager take control? You should, according to Jeni Hooper, a child educational psychologist. Her advice is this: "By the time your child is a teenager you should be aiming for a supporting role as a parent not a directing one. This doesn't mean you step aside, more that you ask what help your teen needs rather than tell them what is required. Finding the motivation to work at evenings and weekends is a tough call, as any harassed executive will tell you, so don't assume your teen will find this easy."
It's not easy to step back and allow your teen to fail - if you count poor exam results as failure, but maybe by standing back your teenager will possibly find the self motivation they need.
More on Parentdish: No, my child is not going to university - so what next?
Our weekly column Surviving Teenagers