Context: GZ grew up knowing it is to call someone a “fool” or “idiot”. It is different than “spoiled egg” in English. She would often hear her parent make remarks under their breath when annoyed with a person at work. 

My interpretation: I think it’s interesting that it is a stupid egg and not a rotten egg. The English version implies there is nothing the egg could do about its unfortunate fate. A rotten egg implied unluckiness. On the other hand, a stupid egg implies deliberate ignorance and inconvenience.