I have one: Ping Pong, the Japanese film from 2002. After watching the bonus features about how they developed the actors' individual playing styles, they revea

I have one: Ping Pong, the Japanese film from 2002. After watching the bonus features about how they developed the actors' individual playing styles, they revealed that the balls were entirely CGI animated. That let the actors focus on the precision of their movements, without worrying about actually volleying! The balls looked a bit odd in the film, but I figured it was simply an artifact of 23fps film capturing a small plastic ball moving at high speed. I never would have guessed it was all CGI. I think I'd seen the movie three times before buying the DVD and watching the special features, years later. So I was fooled in the mid-00s and again in the late 10s.