Helping others carry things is polite.
Johnny comes back from shopping with his mother and there are many bags in the car to bring in the house.
Johnny wants to play video games.
Johnny helps his mother bring the bags in the house before starting to play video games.
Johnny runs in the house and starts playing video games leaving his mother to carry all the bags.
Johnny's mother is really helped by him carrying some of the bags and appreciates his effort.
Johnny's mother has to work hard to carry all the heavy bags from the car.