Purely History on Instagram: "In Rain Man (1988), the phone booth scene where Dustin Hoffman’s character farts was unscripted. Hoffman really did it during filming, and Tom Cruise’s reaction — laughing and teasing him — was completely improvised. Director Barry Levinson decided to keep it in the final cut because the exchange felt natural and added to the authenticity of the brothers’ relationship. It’s now remembered as one of the film’s most charming improvised moments."

How humans make rain - Superstorms, The Science Of - BBC