People shouldn't go back on their word.
A major sale at the mall is happening on the same day that Charlie promised to take Alex to the museum.
Charlie wants to go to the sale.
Charlie takes Alex to the museum and goes to the mall after they leave.
Charlie goes to the mall and makes Alex go to the museum by himself.
Alex has a good time and buys something at the sale with Charlie.
Alex gets mad at Charlie and feels lonely at the museum.