The parents reacting to their children's punishments. Yes, it's mostly their fault for spoiling them all, but still, to watch your young child be sucked up a chocolate tube or turned into a giant blueberry is incredibly horrifying.
The Original Novel
After the first four tickets are gone, Charlie's family nearly starves to death. Even when they arrive at the factory, Grandpa Joe and Charlie are described as bony and skeleton-like (especially Grandpa Joe).
The 2005 Film
One of Mr. Salt's employees finds the ticket. In a heart-wrenching scene, she attempts to hide the ticket but gets caught doing so and is forced to give it up.
To stop the theft of anymore of his recipes, Wonka is forced to close his factory. When he's informing his workers of this, he lets out a soft and heartbroken "I'm sorry" as the gates close.
After threatening to run away, Willy returns home later that day to see that his father kept his promise to not be there if the boy came back: the man and their entire house is gone, leaving a stunned Willy to stare at where the building used to be.
At the end of the movie when Willy Wonka and his estranged father are reunited.
The 2013 Musical
After the fourth ticket is found, Charlie has a Heroic BSoD as his hopes are shattered. As he's encouraged by his dad to make a wish on a star, all he can say is "Don't waste a wish on me," showing how much he had given up hope. This leads into "If Your Mother Were Here," in which Mr. and Mrs. Bucket sing about how the other would do a better job at cheering up Charlie.
The 2017 Musical
Mr. Wonka opening the musical by saying he must go out into the world to find an heir. Then he hesitates because he hasn't been outside in 40 years.
The song "If Your Father Was Here" where Mrs. Bucket tucks Charlie into bed after he despondently says he'll make his birthday candy bar last a year. She says his father was a dreamer and dances with a ghost version of him.
There has been some tributes. Some fan arts for the tribute to the late actors David Kelly (2012; Grandpa Joe) and Christopher Lee (2015; Wilbur Wonka). As the characters mourn the loss.