When you suddenly get really hot in your space suit, and you try to figure out if the fan in your helmet is still working...

When the circulating nurse says I can't pop the scrub sticks in the package, because that makes them unsterile...

When you suggest a surgical move which your attending shoots down, but then after struggling, they end up doing that move...

When the complex case has gone well, and for some reason, the closure doesn't...