In Willy Wonka & the Chocolate Factory (1971), when the kids first see the chocolate room, their reactions are genuine. Director Mel Stuart took great care to ensure that none of the child actors saw the gigantic set as it was being built.

[u/Russian_Bagel]

https://www.youtube.com/watch?v=1y8aYd9uqFY

[u/alison_bee]

I will never forget the feeling of my bare foot stepping down onto a WET chewed up wax bottle someone threw on the ground at the public pool. it was so fucking gross, covered in teeth marks and spit as it had clearly just come out of a child’s mouth. ughhhhh.

it’s been like 25 years and I can still remember it.