There is a point at which Susan David manages to nibble on a small salmon sandwich after it has spent most of the lunch lonely on a china plate.
She's waved away the flute of champagne owing to the fact that she is giving a keynote speech to corporate leaders that afternoon and sips on a brew of English Breakfast.
A psychologist in the faculty of Harvard Medical School, her topic is emotional agility, a term she has coined to loosen up and subdue that nagging inner voice that prevents you becoming the best team person, the best parent, the best partner, the best leader.
Her theories for breaking rigid and negative thinking tumble out rapidly over the course of an hour in the crowded ground floor courtyard of the Cortile Restaurant at the Intercontinental Hotel. Happiness, she is here to tell me, is not something that can be wished for.
"I'm not anti-happiness but," she says - giving great stress to the "but" - ''happiness comes not through pushing stuff under the rug. People who overly strongly focus on this idea of, 'I must be happy, I must be happy', actually over time become less happy.
"What they are failing to recognise is our emotions, our sadness, our frustration, our anger, our emotions, contain really useful data.
"So when you are feeling guilty as a parent - it doesn't mean that guilt is right, emotions are data not directions - beneath that guilt is often a sign that you value being present and connected with your children.
"When you push that under the rug, you take away the opportunity to calibrate and shape your life effectively.
"Or if you are just in the service of just being gritty and being positive, 'keep at it, keep at it', in a career and then five years later you look around and you're like, 'I'm in the completely the wrong career and I've lost five years of my life' you've ... failed to recognise that your frustration is telling you maybe you are in the wrong role.
"When we push our difficult emotions aside we fail to learn from them and recognise those difficult emotions contain signposts to things that we value, and if we can pay attention to the data we can adapt."
David is the author of Emotional Agility, a ''Wall Street'' bestseller that unites research in the field of psychology with the practice of self help.
It began with the Harvard Business Review's publication in 2013 of some of her findings from the 20 years she spent as an executive coach. "The article went viral, completely crazy," she says.
The idea that business leaders could mine their emotions and manage their negative thoughts in ways that align with their values went on to be named by the review as a Management Idea of the Year.
David's clients include Ernst and Young Global, the World Economic Forum, the United Nations Development Program, BHP Billiton, JP Morgan Chase, GlaxoSmithKline, and Nestle.
And you can see why David's ideas would catch on in the workplace: employees are being asked to adapt and retrain at a time of lightning-fast technological change.
But the ordinary person can live a more ''authentic life'', too, by making a few changes to their mindset, David says. One way is to disengage with social media, which she damns as offering "one of the most toxic ways to be in the world'' - living life by ''social comparison".
First there are some buzzwords to learn: "stepping out", that's facing your thoughts in a non-judgement way; "walking your why", that's where our behaviours are motivated or find expression in our values or moral compass.
The Tiny Tweaks Principle is the idea of making small changes to break habits and the choice point - do you binge-watch Netflix or get much-needed sleep?
Some of what David says is good old common sense. Make small changes, not large. That New Year's resolution to lose weight, exercise or quit smoking is never going to work. Put your head in a fridge with chocolate cake sitting on the shelf and your salivating taste buds are the first sign you've lost the battle to diet.
Speaking of food, high tea arrives with a platter of macarons, raspberry tart, tiny cups of creme brulee and scones with jam and cream.
"Thank you, thank you," says David, who is not the least interested in the micro desserts and without missing a beat goes on to explain how her road map to emotional dexterity was shaped and sharpened by David's "gnawing sense of horror" growing up in Johannesburg in apartheid-era South Africa.
A friend was gang raped, her uncle murdered. It dawned on her that the nanny who was a second mother to her had her own children. "She was legislated through apartheid not to be able to live with her children who lived hundreds of kilometres away. She got to see them for 48 hours over Christmas.
"There was this bizarre context of complete legislated hate and legislated divisiveness, so from a very early age I became interested in what does it take internally to thrive in the world, in the world as it is, not in the world we wish it to be," she says.
''The world as it is where life's beauty is inseparable from its fragility and where you can be young until you are not seen; unseen, you can be well until you are brought to your knees by diagnosis."
David's father died of colon cancer when he was 42 and she was 16, leaving her mother with a mountain of debts to clear.
Her ability to get beyond her grief, indeed the catalyst for her entire career, she puts down to a remarkable English teacher, Meg Fargher, at Waverley Girls High School where she studied. Fargher had invited her students to keep a journal the year of her father's death.
So began, what David says was a secret, silent correspondence. "Everyday I would write about my guilt, my sadness, the fact my family life had been changed forever.
"This woman would write back to me questions and poetry. She did something so profound. She showed up to me and she helped me show up to my own emotions.
"And I realised afterwards it was going to, and showing up to, my difficult experiences and labelling them and putting language around them that ultimately helped me not only to get through the experience but to thrive."
As teens they got involved with Linx, a youth anti-apartheid movement through which they befriended a group of students across colour and apartheid lines. South African security forces were unhappy and Farber's phone was reportedly tapped.
David went to university and dropped out. She trained as a secretary, returned to university, and came to to the University of Melbourne to further her studies alongside her doctor-husband who wanted to do a residency in radiology.
They moved to the United States where David studied the science behind emotions, at Yale. They have two children, Noah, 9, and Sophie, 4.
In 2013 David brought together decades of research and many centuries of thinking around positive psychology to edit the Oxford Book of Happiness, a handbook offering the keys to the human pursuit, so she speaks with some authority on the science.
That narrative that suggests happiness is a matter of choice, a way of being, is profoundly destructive. "It is the narrative that basically says if you think about a lovely car it will come your way, a la the book The Secret, and on the surface it looks innocuous."
A friend of David's who recently died from stage four breast cancer had reflected on the "tyranny of positive thinking".
She told David: "What it starts to do is it implicates me in my own death, like somehow I'm culpable for not thinking my way out of ill health, but also what it does is it takes away from my ability to be authentic in the reality of life as it is, and not as life as I wish it to be.
"What I want to do, even in my death, is choose how I live and I want to have real conversations with my family I might not be seeing beyond a month or six weeks - but this feeling that I need to be positive takes me away from that."
The great irony is the pursuit of happiness comes at time of increasing levels of depression.
David quotes the World Health Organisation's prediction that by 2030 depression will be the leading cause of disability, globally outstripping any other form of physical illness.
She insists she doesn't set herself up as someone who has got her life in perfect order. She often trips herself up in her own thinking, emotions and stories. One way of becoming more accepting and compassionate towards yourself is to look back at the child you once were with warmth, kindness and forgiveness.
Tell yourself, as David attempts, that you did the best you could under the circumstances, and you survived.