personnummer. Everyone in Sweden has one; it's like a social security number in the US or national insurance in the UK, but even more so.
In Sweden, even 25 years ago, everything that had to do with the government in any way was tied to one's personnummer. Sooz and I got our own numbers, and I have kept the original document to this day.
When we moved away from Sweden, those numbers were kept, but turned inactive. When we returned to build our stuga, I found we couldn't use them to open our bank account, as personnummers are only for residents. So we had to use a workaround for our bank, the electric company, the tax authorities, etc. Although everything is set now, it was much harder to do without a personnummer. A recent column on The Local describes the problem of the numberless very well.
Workarounds aren't always available. Sooz has been trying to get a bonus card (for discounts and deals) at our local ICA for at least a year. Her application has been either ignored or rejected for various reasons. I called ICA on my last visit and finally got to the bottom of the mystery: we needed a personnummer. Sooz couldn't even get a discount card at the grocery without it. She has a Swedish driver's license, we own a home and pay taxes in Sweden, we're both EU citizens, we both had personnummers, but no number, no grocery card. Annoying.
I heard a story on Swedish radio which indicates I'm not the only one impacted by this numberless status. The National Board of Trade wants authorities to make it easier for foreign nationals to obtain a number, and therefore move more easily into daily life. I'd love to re-activate my old number one day!