"Bamboo joint, bamboo heart" (airtight but empty) is how the older generation of Chinese immigrants in the US used to describe their juniors, meaning that although two worlds are merged in them, they actually understand neither.
竹節（兩頭不透氣）、竹心（胸中空無一物），是往日看不慣下一輩的美國老移民對年輕土生華裔的形容。