Sid’s Bag of Treasure is in every way an exquisite bag of holding, but Sid continues to profit long after the bag has left his possession.
In this culture it is not wise to talk too much good things about anything - especially children,lest some evil spirit steals it. So it is customary to say it is ugly and weak and will surely not survive. Also:
"The man who boasts of his young woman is a fool,
The man who boasts of his wares will get rich."