Founders often try to convince themselves they have PMF. The actual moment of achieving it feels like a sudden, unmistakable change—a switch, not a spectrum—making it clear that all previous feelings were just wishful thinking.

Product-market fit isn't a sudden switch but a palpable shift in momentum. As a founder, you feel the change from pushing against the current (hard selling with little traction) to suddenly being pulled by it (easier sales, inbound interest). This directional change in velocity is the clearest signal that you're onto something.

Founders often deceive themselves about having product-market fit (PMF) after landing a few customers. Replit's CEO clarifies that true PMF is unmistakable: it's when the market is pulling the product out of your hands so fast that you can't even provide it quickly enough. It's a feeling of explosive, overwhelming demand.

Finding PMF is like pushing a heavy boulder uphill. True PMF is the reverse: the boulder is rolling downhill, and you're chasing it. Demand outstrips your capacity, customers stick with you despite imperfections, and the momentum feels like it's pulling you forward.

The moment you find product-market fit is not a time to celebrate; it's a signal that competitors will soon flock to your space. The founder’s immediate reaction was paranoia and an urgent need to build a moat, raise capital, and scale aggressively. The discovery of 'gold' means you must instantly shift from exploration to defense.

The entrepreneurial journey is mentally taxing due to constant high and low swings. The founder's coping mechanism is to anchor himself to what's controllable: delighting the customer. Focusing on product and user feedback cuts through the noise of fundraising, competition, and existential dread, providing a stable focal point.

Founders often mistake gradual progress for product-market fit. The true moment is not a slow burn but an explosive, undeniable pull from the market, which Replit's founder likens to the sudden shock of stepping on a landmine after years of searching.

Being scrappy is crucial early on, but it becomes a liability after achieving product-market fit. Founders must overcome a frugal mindset and quickly deploy capital to scale, a difficult but necessary transition for rapid growth.

Having refounded Notion twice, Zhao advises founders of sideways-moving companies to listen to their "inner body." A drastic reset, like shrinking the team to rebuild in a new location, is often a necessary and liberating move when you feel there's no way out.