Don't get me wrong, The Man Who Knew Too Much is a good film and probably 2 stars is a little harsh.
But I'm comparing this film to other Hitchcocks. The film is incredibly straight forward and was just dull. Perhaps it's because it follows the "man who's in the wrong place at the wrong time" plot that has been imitated for years, but when comparing it to similar films such as North by Northwest, it just doesn't hold up.