Well... this is true for me, when watching movies.
When I'm watching a movie, I can most of the time "read" the charaters very well, but it never works in real life.
Even though I sit by the side-line. Maybe it has something to do with, that you almost never get a confimation that you guessed right in real life.
Or more likely, because movie-makers are trying really hard to give you clues.