Every clarification breeds new questions.
A failure will not appear until a unit has passed final inspection.
Any given program will expand to fill all available memory.
The Ninety-Ninety Rule of Project Schedules - the first ninety percent of the task takes ninety percent of the time, and the last ten percent takes the other ninety percent.
An expert is the one who predicts the job will take the longest and cost the most.
If you improve or tinker with something long enough, eventually it will break or malfunction.