Just because something is unlikely doesn't mean it's impossible. And when you expect that a thing can't happen, it often still does. How else do you explain the Cubs' World Series drought?
There's no reason they should have gone without a championship for a full century, but they went 108 years between titles. And by the end, there was no good reason to expect them to ever win one again. But they did.
Just like the Cubbies, here are a few more things that seem like they shouldn't be possible, but clearly were.