
The Happiness Code – Astrid Groenewegen
A new book from SUE| Behavioural Design Academy
Launching in Dutch, 22 February 2026
Not a self-help book that tells you what to do.
A behavioural book that shows you where to look.
Last year, I was giving a training on wellbeing in Norway. A stunning location. Mountains. Snow in the distance. Oxygen in the air. I talked about how habits are formed. Taking small steps. Rewarding yourself. Everything I knew about behaviour change.
But halfway through, I felt something creeping in. Discomfort. Because everything we were discussing (eating better, moving more, meditating) I already knew. The participants probably did too. And the honest truth? I wasn’t doing any of it either.
Meditation? Started and stopped.
Less sugar? A beautiful phase I now look back on with nostalgia.
Walks after dinner? Somehow dropped out of my system.
A few weeks later, I read the feedback. Some participants said they felt worse after the programme. Guilty. Like they were failing.
That was the moment I realised:
Something fundamental is missing in how we think about change.This book is the result of that realisation. Over the past year, I’ve been on a deep dive to find a better answer. And I’ve found it.The Happiness CodeIt's not about willpower.
It’s about design.
It’s about why change doesn’t stick and how to make it stick, by shifting what surrounds you.
What you’ll learn:
Why willpower is overrated and context is everything.
How small environmental interventions lead to lasting behaviour change.
Why positivity alone can backfire if you ignore the hard parts.
How to activate happiness through curiosity, connection, flow, and growth.
Why you don’t need more motivation, you need better Behavioural Design.
This isn’t a quick fix. It’s a behavioural lens you’ll never want to take off.This book doesn’t give you a five-step plan or a list of habits.
It gives you a way of seeing and shaping the world around you, so that better behaviour happens by default.

