It is wrong to throw a tantrum.
John is a child that is out on a shopping trip with his mother.
John wants ice cream on the way home.
John behaves in public the entire shopping trip and only asks for ice cream when his mother says they are all done and going home.
Thinking only of the ice cream John begins to whine and scream for his mother to finish shopping, so they can go get the ice cream.
John's mother who is happily impressed with his behavior, buys him ice cream on the way home.
Because of John's tantrum his mother decides he does not deserve ice cream, and they go straight home without John getting ice cream.