The decisions that reroute a life tend to be small, low-stakes, and barely worth deliberating over at the time. Kenneth Stanley calls them stepping stones in Why Greatness Cannot Be Planned. They look unrelated to where you eventually end up because greatness is reached through novelty, not by aiming straight at it.
The decisions that have rerouted my life have almost never been the ones that felt important at the time. Choosing a degree, picking a city, accepting a job — those came with deliberation and pros-and-cons lists, and most of them turned out to be far less consequential than I expected. The decisions that actually changed everything were small. A coffee I almost cancelled. A book I bought at an airport because the cover was interesting. A side project I started one evening because I was bored. None of them had a stated objective. They were what Kenneth Stanley would call stepping stones.
Stanley and his co-author Joel Lehman make this argument carefully in Why Greatness Cannot Be Planned, a book born out of artificial intelligence research that turns into one of the most useful books about life I have ever read. Their core finding is that ambitious objectives, when treated as a compass, almost always point in the wrong direction. The stepping stones that lead to a great achievement rarely resemble the achievement itself. Vacuum tubes do not look like the modern computer. The flatworm does not look like a human. In their Picbreeder experiment, where users evolved images by selecting whichever one looked most interesting at each step, the most striking final pictures — a car, a butterfly, a skull — were never discovered by people trying to breed them. They were always reached through a chain of strange-looking intermediate images that had nothing to do with the destination.
Their novelty search algorithm makes the same point with a number that is hard to forget. In a maze-solving experiment, an algorithm that aimed straight at the goal solved the maze 3 times out of 40. An algorithm with no objective at all, which simply rewarded behaviors it had not seen before, solved it 39 times out of 40. The conclusion is uncomfortable for anyone trained to believe in plans: when the goal is genuinely ambitious, optimizing toward it is the slowest way to get there. You do better by following whatever feels interesting next, because the path is too irregular to predict.
I think this is the right frame for the question of which small decision changed your life. Mine, if I have to pick one, was a free evening I spent learning the basics of a tool I had no professional reason to learn. Six months later, an unrelated conversation went somewhere it could not have gone otherwise, and three years after that I was earning a living from what had started as idle curiosity. Looking forward, I would not have picked it. Looking backward, every job and friendship I now care about traces through it. Naval Ravikant has a useful concept here that maps onto Stanley's: the fourth kind of luck, where you build a unique character and reputation, and then opportunities arrive that no one else could have received. You cannot plan for them, but you can become the kind of person to whom they happen.
The pattern across the small decisions that change lives is, in retrospect, pretty consistent. They tend to be cheap to reverse, easy to take, and not obviously connected to any career or relationship goal. They are interesting rather than important. They are usually some form of saying yes — to a coffee, to a class you do not need, to a flight you cannot fully justify, to a piece of writing nobody asked for. And almost always, the decision is followed by a long, unimpressive plateau where nothing visible happens, before the second-order effects start showing up.
This has practical consequences for how I now make plans. I spend less effort optimizing the big visible decisions, because the evidence keeps suggesting they matter less than they look like they do, and more effort making sure my week contains a few cheap, optional, novel moves — a conversation with someone outside my field, a Saturday afternoon spent on something that has no obvious payoff, a book I would not normally read. I am no longer trying to engineer a particular outcome. I am trying to keep the stepping stones visible, knowing that the one that matters will not announce itself, and that the only way to find it is to keep moving toward whatever looks interesting from where I am standing.
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