Knowing the hero will win does not make you smart. Most people go into films knowing the outcome (even when the hero doesn't win). That's not why people like seeing films. It's for fun and it is an escape. When you're watching a movie you don't have to think about work, family, that doctor/dentist appointment you have been putting off..

I don't think you are "stupid again", I think you have matured more. Your previous opinion is similar to what a lot of teenagers go through when they think they know everything.