Much to my (no doubt childish) amusement, Chris Liddell, who was, when I saw him, the chief financial officer of General Motors, sent an email with the address of his sister's house in Remuera, which is where we were to meet - and he got the street number wrong.

This is funny because he is a very, very high-powered numbers man. So of course the first thing I said was: "This is a good look for a chief financial officer, isn't it?" He said it was a test of our initiative, to see whether we could track him down. That was pretty swift thinking, so I'm going to give him nine out of 10 for his initiative.

I give him top marks for being able to take a ribbing. Before I went to see him somebody said: "What do you want to interview him for? He's horribly dry, and boring."

He has a dry sense of humour, certainly. He said, about the wrong address: "I've always struggled with numbers."

He showed no signs that he was struggling with not telling me he was about to become an unemployed numbers man.

I heard this on the radio, the week after I saw him. He has just quit GM, in what is being described as a "shock" announcement. It was certainly a shock to me. He may have heard me swearing in Detroit because he emailed to say, rather casually, I thought: "You may see some news about me today."

When he took the job at GM, they were in strife, requiring an unpopular and humongous government bailout of US$50 billion ($68 billion) and his job was described as the toughest job in finance, in the world. Which is exactly why he wanted it. He never finds challenges frightening. "No, the opposite." He finds them invigorating. "Yeah."

And now just over a year since he got the toughest job, he doesn't want it. Perhaps he is sufficiently invigorated, for the moment. I do (I write through gritted teeth) understand why he couldn't tell me. But I asked questions which now seem silly: about how much he wanted to be the next CEO (he missed out in August). He laughed at me and said you didn't go into jobs letting it be known you were after someone else's job.

I should probably have pricked up my ears when he said he did want to be a CEO again (he was head of Carter Holt Harvey from 1999 until 2002), but I didn't think he meant next week.

I emailed to ask if he had quit because he had the huff. He replied: "No, I don't get the huff. I don't have firm plans ..." There is speculation that he's up for the Fonterra job. "No comment." I'd take that as a yes. "Ha.

Maybe. Maybe not. Don't believe everything you read in the paper." On the day he was taking calls from serious business journalists from around the world, he was emailing me instructions on how to get my computer to make those smiley face things. He said he was multi-tasking.

He is fiercely ambitious, or competitive. That much you can find out from reading about him. There ought to be an easy way to find out what he is really like: Make him play his real initiative test. He uses this trick when he's interviewing people for jobs and asks them to provide the three words which would best describe themselves.

The trouble is, he's not at all willing to do this. And you have slightly more chance of persuading him to do something he doesn't want to do as you would of persuading your bank manger to give you a $50 billion loan. So one of my words for him might be: stubborn.

He was home for his holidays. He does not have what most people would call a holiday. This is what he did on his: He fronted the opening of Rotoroa Island, the site of the former Salvation Army rehab centre, now restored and gifted to the New Zealand public as an arts and conservation area.

He is on the trust, and is friends with Neal (his former boss) and Annette Plowman, whose $30 million act of philanthropy Rotoroa represents. He went back to his old school, Mt Albert Grammar, to present the 2010 Liddell Scholarships. He mentioned this only because I asked what he puts his money into, given that he is a great fan of philanthropy.

He has said he won't be leaving his children money. (He has two, and three step-kids from his second marriage and is about to "get another couple".) He says he'll buy his kids a house and while he doesn't say what manner of house, that'll be about it. I said he was a miserable bugger. He said he thought inherited wealth was more likely "to spoil someone's future rather than enhance it".

He quoted Andrew Carnegie in his Rotoroa speech: "The man who dies rich dies disgraced."

Oh, he doesn't really believe that. "I think that may be a little extreme. It's a nice catchy phrase." And "might", actually, leave his kids some money. "But I don't tell them that!"

He was planning to play a bit of golf. He had that conference call. He spent a ridiculously generous amount of time answering my emails (we had a rather rushed interview because of that wrong address, so he offered to fill in any gaps).

He was also, presumably, planning to spend some time with his fiancee, Renee Harbers, who was in Auckland with him. She's an American from Seattle who runs the Harbers' Foundation, a philanthropic trust, set up after the death of her first husband in a plane crash. They get married next month, hence the new lot of stepchildren.

God knows how he found the time for romance. "My day, normally speaking, is: I go the gym in the morning, I go and work for 10 or 12 hours, I have dinner, I go to sleep."

It seems unlikely that he is a romantic, but why else bother marrying three times? He doesn't believe in God, so he could just live with people, surely. He emailed an answer to the question of romance: 'I think I have some romance in me - although I'm not sure it would make the finals of the three word game.

Okay, I can see you saying, give me some examples ... Renee woke on her (milestone) birthday to a vintage car built in the same year she was, with a big bow around it. I regularly send her flowers and do the small things that I think make a difference in a relationship."

He'd probably never have mentioned his wedding had I not asked about his previous marriages, and he probably regretted it, because I emailed A Very Important Question: Had he bought Renee a stonking big rock for her engagement ring? "No, she doesn't need status symbols ... It's a good size but not observable from space."

I'd asked about his first two marriages because I wanted to know whether he'd ever failed at anything - his does seem a charmed life. He might count two divorces as failure. He doesn't, although he does say that three marriages is a lot of marriages, "by most people's standards, so there you go".

By his standards? "Aah, yeah. Sure. No one starts his first marriage thinking they're going to have three. So, yeah, sure." I asked whether he'd examined whether his ambition had got in the way of his marriages and he looked a bit stunned. "Aah. No!" A mate of his once said that he was the most fiercely competitive person he'd ever come across.

"Ha, ha. Which is possibly true." But he says I confuse ambition with competitiveness. So I suppose the question should have been whether he's exhaustingly competitive to be married to. He says he doesn't always have to win at Scrabble so perhaps the answer is: not always.

I attempted to get him to play his interviewing game by giving him one word to kick off with: Ruthless. A headline from his Carter Holt Harvey days described him as an Axe-wielding Boss. He's made more than a few people redundant.

Would it bother him to be thought of as ruthless? He says it would. Would it upset him? It is the having to do things like make people redundant that upsets him, he says, not how he's perceived by headline writers. A belief in philanthropy does not, he says, sit oddly with what I call ruthlessness. He counts Bill Gates as a "secondary friend", which means he sees him a few times a year, and, "he is certainly ruthless ... but also a very generous heart".

But we were supposed to be playing his game.

I told him he was terrible at it and he said, "No. It's just that I'm not willing to share it with you. That's different." He didn't want to risk giving away anything about himself. "Yeah."

Later, by email, he said: "OK. You wore me down."

But he has to keep the upper hand, so he made up some rules. Before I was allowed to look at the words he thought best described him, I was to "do the following thought exercise. Write down the three you think apply to me, and compare them." Also, as part of the deal, he would provide three words that best described me, and I was to do the same. All I'm going to say is that he got two right and one wildly wrong - and I don't want to give him the satisfaction of knowing which one.

Anyway, his are: Smart, he says he was lucky to have been born with a good brain; if not the "highest IQ in the room"; Driven; Patriotic. He asked me not to put these in because he didn't want to come across as arrogant. But because, the cheeky sod, he sent a follow-up email saying: "Try the game with your friends (I assume you have some ... )", I have.

My words for him were: Confident; Driven; Empathetic. Was he surprised at the last one? No, he said, but he thought he was better at concealing it. That might have been a poke at me insisting on his ruthlessness.

How much does this tell us about him? He was presumably in the middle of quitting his very big job at the time, and he found quite a lot of time to play a daft game with me via email.

So, dry and boring? I never thought he would be.