Little Shanzi was very clever and quickly joined in playing with the younger members of the household, but the smart little fellow also vividly remembered his status as a servant and never overstepped his bounds—an attitude likely reinforced by daily reminders from the adults.
Xiaofeng, on the other hand, was delighted, finally having someone to play with him. Although there was Zhou Xiao, he was always following Sanni around and didn't have time for Xiaofeng. So, now that he had someone to play with every day, he was naturally excited beyond words and even started teaching Little Shanzi to read.
As for Xu Shou and his wife, they were both quite reserved and rarely showed much expression on their faces. However, they were incredibly diligent, probably aware that as bonded servants, they generally wouldn't be highly valued by their master's family. Therefore, the couple tended not to put themselves forward and were rather self-aware.