The downside of thinking you're infallible goes up the closer to infallible you get.

When you're very far, it's very clear to everyone that you're not infallible, and they'll take actions to hedge.

This hedging creates resilience because it caps the downside.

But when you're very close, you start believing it, as does everyone else.

And then in the times you don't hit it, it's dangerous because it will surprise you and others in a big way.

Even the most galaxy brained person, the most impressive organization, are imperfect earth-bound entities.

No one and no thing is infallible.