the result of an error in judgement

This is what happens when you take the gamble on the smaller rawl plug/screw combo rather than the heavy duty ones. I successfully put up the shelves and they were looking pretty good. Half way through putting books up and they start to come off the wall. There I am holding the shelf up with one hand and throwing our precious books onto the bed/floor with the other.
Given I could only work in half hour bursts yesterday 'cause of this blasted cold, that was quite hard work.