A hypothetical example would be one person spending a week or two setting up an extensive in-house Spark cluster to solve a problem that a second person in one day realizes can be solved on one machine using some clever shell scripting tricks. The former person knows a lot and may have been fully capable of the solution the second came up with, but they followed the wrong guiding principles in analyzing the problem and arrived at a solution of considerable complexity.

An alternate formulation of this would involve the second person above arriving at a new job, observing that they're using Spark on an expensive cluster to regularly perform a computation, and noticing that actually they could do the whole calculation on a single node using simpler tools.