Ah! I have another example like that. Sometimes people use the term 'quantum leap' to describe some huge change. As it turns out, a quantum leap is a very small change in the state of an electron, a very tiny event, nothing to write home about.
The point about a quantum leap is that it is discrete, rather than continuous, so, for example, a "quantum leap in understanding" implies a progress in understanding that cannot be broken down into a progression of small increments of understanding.