"The Ark of the Covenant was perfect. The Sankara Stones were way too esoteric. The Holy Grail was sort of feeble—but, at the same time, we put the father in there to cover for it. I mean, the whole reason it became a dad movie was because I was scared to hell that there wasn’t enough power behind the Holy Grail to carry a movie. So we kept pushing to have it function on some level—and to make it function for a father and a son. To make it that kind of a movie was the big risk and the big challenge, but also the thing that pulled it out of the fire. So, at the end of it, I was like, No more of these, baby. We’re done. I can’t think of anything else. We barely got by on the last one!"
January 1, 1970
https://en.wikiquote.org/wiki/Indiana_Jones_and_the_Last_Crusade