Afterwards she told me that it was a landmark event in her life, that she became a counsellor 18 years ago to make a difference in people's lives but this was the first time anyone had ever returned to tell her that she had. I felt the ¬power of this gift and wondered why I didn't - why we don't - do this kind of thing more often.
We talked for another half hour or so about our time together, about how my life had changed for the better, about how much I appreciated her role in that. It was one of the most meaningful experiences of my life.
The gratitude letter was the tenth of 11 happiness ¬practices I undertook over 10 weeks as part of a free online course called "The Science of Happiness", delivered by the University of California, Berkeley.
The course offered an overview of the science of what makes us happy and why, and it provided research-tested ways, like the gratitude letter, to bring more of it into our lives.
I have quite a history of being morose. In the past seven or eight years, I have twice been depressed, once medicated. I'm much happier now. I hit the jackpot in terms of a wife and we have a fantastic 18-month-old daughter and a kumara-sized fetus.
These things bring me much joy. But something in me, something probably quite unhelpful, can't help but ask: "Could things be better?"
We can't afford to buy a house. This dominates my thinking. I need to find more work but there is so -little time. For a long time recently my bed sheet was smeared with what I hoped was Marmite, and cleaning it was well down my priority list. My daughter is nightly sleepless and therefore so am I.
When people ask me how I am, rather than saying, "Good", I complain endlessly about sleeplessness and my inability to buy a home.
So yes, I thought, things could be better, for sure. But couldn't they also be a lot worse? Unfortunately I didn't have time to think about that question - I had already started week one.
The study of happiness as a serious scientific discipline is a relatively recent development but it is already a massive one. I have been interested in it for about a decade. On my bookshelf, alongside whole volumes of shameful self-help nonsense (Never Eat Alone, How to Work a Room, How to Be More Interesting) are several of the landmark tracts: Authentic Happiness, The Happiness Hypothesis, Happier.
My interest in and acquisition of these books came in a period of vague unhappiness and dissatisfaction, but pre-dated my depression.
Was that correlation or causation? I couldn't tell for sure, and thus my unease. What if I'm prone to depression and this kind of obsessive search for happiness is just triggering it?
Psychologist Martin Seligman, one of the founders of the modern happiness science, talks about how traditional psychology takes people from minus five to zero and positive psychology takes people from zero to plus five. What if I'm just a natural minus five? Maybe I should just stay focused on getting to zero.
This is not a claim without foundation. One night a few weeks ago when we were looking at houses and I was talking about how everything was hopeless, Zanna - exasperated by my endless espousal of this narrative - said to me: "I look at life through rose-tinted glasses and you look at life through black glasses - thick, black, tar-covered glasses. Like, covered in thick, thick, black goop." She demonstrated with her hands the thickness of the goop, which hung in great strands from my imaginary glasses.
I laughed, but also wondered if that was fixable.
The first two happiness practices of the course were "three good things" and "active ¬listening". In studies, people who are actively listened to, as opposed to being given advice or simple acknowledgement, report feeling more understood at the end of a conversation. People who have done the three good things exercise still show increased levels of happiness six months later.
I tried the active listening with Zanna but it was impossible to remember all the instructions: paraphrase, ask questions, express empathy, use engaged body language, avoid judgment, avoid giving advice and take turns.
"Why do you keep looking at your computer?" she said after a few ¬minutes.
"I'm reading the instructions," I said "Mmm. Would you call that active listening?" she asked, and I knew that question was rhetorical.
"Three good things" involved writing down three things I was happy about that day. I wrote things like: "Zanna and I did our budget and it was good" and "Tallulah cuddled me a lot" and I did feel good about them. But I didn't feel that doing this every day was going to change my life - I wasn't really motiv-ated by it.
The first thing I noticed about this course, as a time-poor person, was that the happiness practices quickly piled up. I felt overwhelmed and realised if my happiness was not to be compromised, I had to be selective about the ones I invested time in. They had to feel meaningful to me.
If you follow the instructions for "Five random acts of kindness" (week three) it could take anything "from several minutes to several hours".
Researchers have found people who perform five different acts of kindness for five different people one day a week for six weeks see a significant boost in their happiness.
My first thought was: "How will I ever do five acts of kindness in one day? I probably haven't done five acts of kindness in the past year." This belief was subsequently reinforced by others.
In the morning, I sat in a cafe in Mt Eden with a five dollar note in my pocket, thinking about handing it to the staff and asking them to use it to pay for the next customer's coffee.
I liked the idea but Mt Eden was the wrong place for it. Chances were the next customer would earn more than five dollars in the time it took to say, "A five dollar note! How quaint!"
I called my mum. "What were you calling for?" she asked, after we had talked about her problems with her teeth. "Just to ask about your teeth," I said.
I could feel her amazement and scepticism but she told me she appreciated it. Later in the conversation, after a pause, she said: "Do you need me to babysit?" "No," I said, a little angrily. That was one. I felt pretty good about it.
Next, I emailed someone I owed a debt of gratitude for having gone out of her way to help me in my career. I told her how much she had helped me and how much it meant to me. She emailed back saying I had made her day. That made my day. That was two.
I left the cafe. It was nearly midday on one of the hottest days of summer. I saw a postman who was sweating profusely.
I crossed the road and said, "Hey mate! Get yourself a drink at the end of the day!" I held out the $5.
My heart was pounding. I worried he was going to reject me, that he probably wasn't allowed to accept money, but he smiled and said, "Thanks, ¬buddy!" and slapped me on the back. I held that slap close.
I spent most of the day thinking of kind acts I could do. It was draining. I didn't do much work.
I remembered our neighbour had recently seen a book on my bookshelf she had read and liked so I found another one I thought she might like and I took it to her. We had a nice chat about books.
We had friends coming for dinner so I went out to buy beer.
While I was there, on impulse I bought an extra fancy bottle for a beer-admiring friend I knew had the afternoon off work, and I drove it over to him.
He asked me why I had done it and said he thought this was the first time I'd ever bought him anything.
He seemed grateful and mystified, which became the standard response from people who knew me. I felt good about doing these kind things, but also a bit disappointed in the me that was reflected back.
"Is this maybe telling you something about yourself, honey?" Zanna asked when I told her about it later.
"Like the ghost of no kind¬nesses past?" I said. She didn't laugh. "Great," I said, "you're telling me I'm not kind enough to you."
"Not me," she said. "You're very kind to me. But it's a fact that you don't call your mum except to ask her to do stuff for you."
On the drive home from delivering the beer, I stopped and let a car across Great North Rd. That's no small kindness at 4pm.
I thought about how, when I got home, I could take my daughter out so Zanna could have a break. I didn't do it, but I felt good for having considered it.
As a thought experiment, at the end of the day, I recalled the night a couple of weeks before when I had come home from a night out feeling upset and disconnected, like
I was a long way from who I wanted to be.
That night and that feeling, which had stayed with me like an annoying background noise, now felt so far away it was like it belonged to a different person.
The Science of Happiness" is a relatively long course and this is a relatively short article and is therefore necessarily reductive.
The course had hours of videos, and thousands of pages of readings and research, offering a multitude of pathways to improved happiness: mindfulness, social connection, forgiveness, co-operation, gratitude, awe, play.
It is not possible to remember all of them, let alone act on all their recommendations.
The best we can do, I think, is to focus on what resonates most for us and to build that into the way we see and live our lives.
Midway through the course I came across a quote from Darwin, saying the communities that flourish best would be those that included the greatest number of the most sympathetic members.
I liked that a lot - the idea that kindness towards others is at the heart of human flourishing. That's a much more hopeful conception of natural selection than "survival of the fittest". If evolution is selecting for kindness rather than strength, the world doesn't seem nearly so harsh.
I will forget most of this course, or at best hang on to it in the vaguest possible sense. But I will never forget the sharp pleasure of my day of kindnesses, and the meaning and sense of connection that came with delivering my letter of gratitude.
I've never really been an optimist but I've always wanted to be and I think that's why I'm so attracted to these practices.
If kindness makes us happy and makes the world a better place, let's go with that.
