So, in quantum mechanics, large deviations from the "classical" mean are like opposite direction…
So, in quantum mechanics, large deviations from the "classical" mean are like opposite direction waves. A positive wave and a negative wave cancel one another out. This is similar to in probability theory where large deviations from a mean are rare. (It's actually the same if you switch to imaginary time.) So, you can think of this as like out of phase waves interacting and canceling each other out, leaving only the mean.