Honestly, it’s the cheap thrill of “I’m about to drop something big.” The stranger’s a quick cue that the narrative’s shifting gears, so you keep watching. They’re a cheap plot device, but they also give the audience a secret‑keeper vibe, a little thrill that “you know something I don’t.” It’s irresistible because it satisfies that craving for a surprise without having to rebuild the whole story. And if you’re clever, you can read the cue and call the bluff. But hey, sometimes the stranger just ends up being the biggest joke of all.