Human beings love to think we know everything and that can predict the future. But in reality, we know very little, and the future has a way of taking turns nobody could ever expect (sorry, online psychics, even you). That's why there's always a risk when confidently expressing predictions or opinions online that those posts will age like a bag of spinach. And even though tweets or posts can be deleted, screenshots live forever, pixilated time capsules of shame for the world to see. Ooooooops.
The "Aged Like Milk" page on Reddit collects screenshots of posts that did not hold up well with the passage of time.