A conclusion reached too quickly often spends years defending its head start.

The first conclusion has an unfair advantage. Everything encountered afterward gets interpreted in its light, and abandoning it means admitting the intervening time was spent defending something arrived at too fast. So the early guess accumulates support and becomes progressively harder to dislodge, entirely because of when it appeared rather than how well it was reasoned.

When you reach a conclusion quickly, mark it as provisional and say so out loud. Deliberately generate a second explanation before gathering more information. The moment you have two candidates, everything that follows starts working as evidence rather than as reinforcement.