I haven't seen this movie in years yet just thinking about it, I can vividly recall parts that make me bust out laughing. You can tell the cast worked hard to keep their composure during some of Danny Kaye's antics. You can actually see them working to keep from busting out in laughter. They demonstrated a lot of professionalism. I can only imagine what the out-takes are like and how the crew might have had to be muzzled to keep from ruining miles of film footage.
Review of The Secret Life of Walter Mitty
