What is the most abhorred circumstance when refining pills?
There are many, many factors, such as errors in controlling the flame temperature, mistakenly determining the proportion of ingredients, misidentifying the type of ingredients, and so on.
But many of these can be controlled. As long as one is careful and cautious, these problems can generally be avoided.
However, there is one thing that's hard to control for Pill Refiners, and this can be referred to as an unexpected event.
That is the destruction of the Pill Furnace!
This is very difficult to predict, as the material of the pill furnace is typically hard and resistant to burning. Many pill furnaces tend to improve in quality the more they are used.
Still, the destruction of the pill furnace is an inevitable occurrence. If it happens during pill refining, it usually spells doom for the batch of pills in progress.