It's good for siblings to share things with each other.
John is eating cookies in the kitchen when his brother, Tom, walks in and asks if he can have some.
John wants to respond to Tom.
John tells Tom that he would be happy to give him some cookies, and they eat the rest of the cookies together in the kitchen.
John tells Tom to find his own cookies and John eats the rest by himself.
Tom feels grateful to his brother and glad that he was able to enjoy the cookies.
Tom feels upset by his brother's selfishness.