It's polite to share duties.
The house needs to be clean, and Wang and his brother Charlie are supposed to do it.
Wang wants to hang out with his friends.
Wang tells his brother he's in a hurry, and asks if they can work fast.
Wang leaves without telling his brother, and without doing the chores.
Wang and his brother complete the chores fast enough for Wang to go out.
Wang's brother is forced to clean the entire house completely alone.