Walking on Eggshells

Began as "walking on eggs," recorded from the late 16th century, with the Oxford English Dictionary defining the older form "tread on eggs" as walking warily, as on delicate ground. The "eggshells" version took over by the mid-1800s, appearing in Wilkie Collins's novel The Woman in White (1860). The image likely draws on the much older "Egg Dance," a traditional entertainment dating to at least the 15th century, in which performers hopped and danced around eggs scattered on the floor without breaking any, a literal demonstration of extreme care.