But in the evenings, when Charlie, his beloved grandson, was in the room, he seemed in some marvellous way to grow quite young again. All his tiredness fell away from him, and he became as eager and excited as a young boy.

This early description of Grandpa Joe comes from Chapter 2 (Mr. Willy Wonka’s Factory). One of the most important characteristics of Grandpa Joe is his powerful and spirited inner child. Even though he’s the oldest of the grandparents, being around Charlie’s youthful energy invigorates him. All the grandparents participate in telling the stories about Willy Wonka, but Grandpa Joe always takes the lead. He has a clear love of wonder and whimsy, foreshadowing that he’s the ideal adult to accompany Charlie into the factory.

“He’s brilliant!” cried Grandpa Joe. “He’s a magician! Just imagine what will happen now! The whole world will be searching for those golden tickets! Everyone will be buying Wonka’s chocolate bars in the hope of finding one! He’ll sell more than ever before! Oh, how exciting it would be to find one!”

Grandpa Joe has this reaction to Willy Wonka’s announcement about the golden tickets in Chapter 5 (The Golden Tickets). Throughout the book, a lot of adults see only madness in Wonka’s behaviors, whereas Grandpa Joe can usually find the logic in it. While Grandpa Joe is by no means as eccentric as Willy Wonka, he has a deep appreciation for the chaos and wonder that Wonka creates. As one of Charlie’s parental figures, he passes on this appreciation to Charlie.

The colour was rushing to his cheeks, and his eyes were wide open, shining with joy, and in the centre of each eye, right in the very centre, in the black pupil, a little spark of wild excitement was slowly dancing. Then the old man took a deep breath, and suddenly, with no warning whatsoever, an explosion seemed to take place inside him.

This passage describes Grandpa Joe’s miraculous rise from bed in Chapter 12 (What Is Said on the Golden Ticket) after Charlie finds the golden ticket. The combination of his beloved grandson getting a change of luck and the possibility of getting to experience for himself the wondrous chocolate factory physically invigorates him. Implicitly, Grandpa Joe has been in bed for so long not just because of his age, but because the dreariness of the family’s poverty has left him with no excitement or energy. The golden ticket has reawakened his childlike wonder and sense of adventure.

“Of course they’re joking,” answered Grandpa Joe. “They must be joking. At least, I hope they’re joking. Don’t you?”

Grandpa Joe makes this comment at the very end of Chapter 17 (Augustus Gloop Goes up the Pipe), after the Oompa-Loompas sing their song. Although Grandpa Joe is on board with much of Willy Wonka’s whimsy and chaos, this comment emphasizes that he is kinder than Willy Wonka and a much more traditional adult role model. Grandpa Joe’s worry after the Oompa-Loompas gleefully sing about Augustus being turned into fudge is an expected and compassionate reaction. While Grandpa Joe has no problem criticizing the bad children for their behaviors, he doesn’t want them to be in danger.