When they ask me a question, “What is the single most important thing?”, my answer is always, “The single most important thing is not to look for the single most important thing, because the world is complicated.”
When a couple who are about to get married ask me, “What is the most important thing for a happy marriage?” My answer is “The single most important thing is not to look for the most important thing. For a happy marriage you need to get thirty-seven things right, and if you get thirty-six things right and you disagree about sex or you disagree about religion, the marriage will fall apart.”
So to go to your question, “What is the most important thing we have have to get right?”, the most important things that we have to get right are climate change, inequality, and nuclear risk – the risk that we will have nuclear war and that we will have a nuclear winter.
Conversations with Tyler – Jared Diamond on Leaders, Luck, and Irreplaceability (Ep. 289)