Why do some movies feel way too long?

A lot of movies drag because they're stuffed with scenes that don't move the story forward - think of those long, pretty shots of characters walking through hallways or having conversations that repeat what you already know. The pacing matters too; if a film cuts slowly between shots or lingers on moments that don't build tension or character, your brain gets bored even if the runtime is only two hours. Some directors also struggle to cut their own work, so scenes that seemed important during filming end up just sitting there dead weight on screen.