Nothing too complex. I come from a culture where you take one last name from each parent. No hyphen. Just FirstName LastName1 LastName2.
Some systems put LastName1 as my middle name and shortened it to one letter. Some excluded LastName2. Some squished both last names into one name, sometimes with a hyphen, sometimes not.
But because every system did its own thing, no one could ever find me. I had 2 different credit scores at one point. I received 3 voting cards every election, all of them wrong, despite the fact that every election cycle I would take the hours it takes to report the errors and get them to “fix” it. I was enrolled twice in one class in grade 4 under two separate wrong names. And whatever name my high school used on their system, I wasn’t showing up when universities searched for my records, so I kept getting rejection letter after rejection letter with no explanation and it took me months to track down the cause and have it fixed, by which point it was too late to get into several schools. I also couldn’t buy certain things online because some stores’ paymentet methods wouldn’t let me put in the name of my credit card as it was written. Oh, and the government couldn’t get the name on my social insurance card and the name on my taxes to match. This affected my online logins, so I would need to call on the phone to verify myself for each tax-related transaction, including simple address changes.
But first, the person banning water would become the ultimate serial killer.