It is a really good movie, with a great cast of kids, a thrilling but not too scary plot, and every '80s throwback you could desire. One can also appreciate the story for including a Jewish character, even when that boy is the least developed character among the main group of children. As a coming of age story, what better way to show this than seeing him study for his bar mitzvah ceremony?
However, the movie got something very wrong. In an early scene, Stanley (the Jewish kid) is standing in the synagogue, struggling to recite the Torah aliyah blessings. His father, who happens to be the rabbi, is upset because it makes him look bad.
In a close up shot, you can see that Stanley is holding his chumash upside down!
No wonder he was struggling to read the blessings.
I find it hard to believe that there was not a single person on set who caught this error while filming. There are a few logical in-universe reasons why Stanley could have held the book as such. Chances are that Stanley had memorized the blessings rather than try to read the Hebrew, thus he was not even paying attention to how he held the book. Or perhaps he was holding the book correctly, but the cover was bound the wrong way (I have seen this happen at least twice).
Or maybe Stanley is so advanced that he can read Hebrew upside down, meaning that Hollywood is once again holding us up to an impossible standard.
Whatever the reason, for a film about a supernatural entity that takes the shape of a clown to terrorize and kill children, this error makes the movie difficult to believe.