When I had just started in genealogy, back in 1990, I was looking for one of my ancestors, Hendrik Brinks, the father of Egbert Brinks (1800-1867).
I knew he died in 1852. His death certificate states he died aged 80 on 14-Jun-1852, and that he was born in the village of Holten.
So I had to look through the baptisms of Holten from 1771 and 1772 to find him.
Lo and behold: on 23-Feb-1772 Dirk Brinks and Hendrina Hendrix (Dutch women are always mentioned by their maiden name in the Netherlands, even back then) had their son Hendrik baptized. Found him!
I found the marriage of their parents, their baptisms, and later on their ancestors as well: three more generations before hitting my brick wall(s).
Fast forward to 13-Aug-2018: my favourite genealogy show "Verborgen Verleden" (Dutch version of the BBC-series "Who do you think you are") has an episode on Tom Egbers, then a well known Dutch sports presenter.
While watching the show, my attention is peaked when I see some familiar names and villages when they show parts of his ancestral tree. It turns out that Tom Egbers and me are 5th cousins, since Tom descends from Jan Albert Brinks/Egbers (1809-1883), a brother of my ancestor Egbert Brinks (1800-1867).
The TV show names their father as "Hendrik Brinkes/Egbers/Vlikkers" (1771-~1810), a slight deviation from the "Hendrik Brinkes" (1771-1811) I found back then. But that is completely understandable, since people in the east (and north) of the country often took the name of the farm where they lived as their surname (quite common in those regions until Napoleon demanded fixed surnames in 1811 by law - 98% of the surnames were fixed after that, the last 2% being fixed by another law in 1825).
But the TV show has Hendrik's father as "Egbert Brinkes" (1741-1797), not the Dirk Brinks (1734-1807) I found over 27 years earlier... Huh?
So, after rewatching the show to see if I understood that correctly, I immediately look up the baptisms in Holten in 1771/1772 (conveniently available online, so I didn't have to visit the provincial archives like I had to in 1991). On the same (2-page-)scan that shows Dirk Brinks on the right page, who has his son Hendrik baptized on 23-Feb-1772, there is also a "Echtbert Hendriks" on the left page, who has his son Hendrik baptized on 30-Jun-1771. It mentions his mother "Leida" (no surname) and "Hendrina Hendrix" as the witness.
After some more research it turns out that the woman named "Hendrina Hendrix" (Dirk Brinks' wife), who is mentioned on both baptisms, is actually an AUNT of Echtbert/Egbert's son Hendrik, making both Hendriks eachothers cousins!
The Dirk Brinks (1734-1807) and Hendrina Hendrix (1739-1802) I considered to be my ancestors, were NOT my ancestors after all!
But, luckily, Hendrina Hendrix' brother Echtbert/Engbert/Egbert Brinkes/Brinkhuis (1741-1797) and his wife Aleijda/Leida van de Horst (~1745-1807) ARE my ancestors, so all the research I did in 1990 on the ancestors of Hendrina Hendrix is still useable, as they are (of course) also the ancestors of her brother Echtbert/Engbert/Egbert.
I had to do new research on Echtbert/Engbert/Egbert Brinkes/Brinkhuis, and even got back one generation further than on Dirk Brinks' ancestors...