Gobstopper
Why did Charlie give the gobstopper back? He promised not to show it to anyone else, not to give it back.
shareJust bad writing.
They thought Roald's ending didn't tug the heartstrings enough, so they had Charlie be first shut out of the lifetime chocolate promise then give back a gobstopper to Willie anyway to show he was somehow deserving of the factory.
Why would Charlie give back the gobstopper? It was a gift from Willie to all the kids.
Forgetting that, in order to get that scene of Charlie giving up a Gobstopper, they had Charlie act like every other spoiled child - specifically break Willie's rules. The only difference between what Charlie did and the other kids did was that Charlie didn't get sucked into a tube, or shrunk, or turned into a blueberry, etc. In other words, he got a second chance the other kids never got.
Bad writing.