Watching and enjoying films always comes with a certain degree of the suspension of disbelief. On an obvious level, there's fantasical elements like alien invasions, high-profile conspiracy, or basic magical formulae. But to look at things in a more subtle light, real life is unlikely to bring about such specific events will occur in such a specific order that fantastical outcomes prevail. That applies to your Wonka's golden tickets, your Bruce Almighty "chosen by God for the meme," or the intricate planning that brought about the Murder on the Orient Express.
As an audience, we can get on board with all of these phenomena quite easily, as long as everything is logical. Sadly, sometimes a film takes a step outside its self-contained boundaries that we start to have issues. As soon as you have to ask, "Wait, why did that happen?" or, "Shouldn't they have just done xyz?" you're in trouble. And if a plot couldn't progress without a specific McGuffin, chances are there'll be some quizzical looks on the faces of viewers.
Maybe it's time we had a look at some movie moments that had us scratching our heads at plot curiousities or, worse still, table-flipping at the downright idiocy of those on screen characters.