You shouldn't take someone's food.
Chris just finished eating lunch in the school cafeteria and is still hungry, but his friend James has a whole tray.
Chris wants to eat more.
Chris sees James step away for a moment but waits for him to come back to ask to have some fries.
Chris notices that James walked away for a moment and takes his french fries.
James feels for Chris so gives him half his fries and is glad he was asked.
When James comes back he sees Chris eating them and is now mad at him.