You joke but back in the 90s when I first used the internet in the library I had to choose a password for the email. And the requirements were weird. Needs to be an exact length, letters, numbers, and so on. Then I realized my country SSN was a perfect match with the requirements! "Wow that's perfect, so I gonna use that as a password, nobody gonna guess that" - the naïve boy thought. Of course it was hacked by some other classmate that got the same conclusion and I realized that it wasn't that perfect and that almost everyone had the same idea due to the strict exact length requirements. (SSN in my country can be easily found again if you know name and DOB)