It is bad to use money intended for someone else.
Ned's mom gives him some money to buy Advil at the drug store and Ned also has his own money.
Ned wants to buy a candy bar.
Ned purchases the Advil with the candy bar, but only uses his own money for the candy bar.
Ned buys the candy bar along with the Advil with his mom's money and doesn't give any cash back to his mom.
Ned's mom thanks Ned for the change, and they both share a candy bar while talking.
Ned's mom notices he bought a candy bar and scolds him for using her money, while Ned cries.