During WW2, the Allies wanted to armor their planes better so more would survive missions. But armor is expensive and heavy so you’d have to prioritize where to put it.
So they go out and collect data on the returning planes to see where they’d been hit. That picture is basically the data collected: where returning planes had sustained the most damage.
So most of the engineers looked at that and went “Aha, the points with the most damage should be armored, since they get shredded up pretty good.”
And one engineer went “Um actually, if they got shot there and came back, armor doesn’t matter. We need to armor the spots with no bullet holes, since a plane shot there wasn’t able to return.”
And so it was, and they called it Survivor Bias.
In this case, it’s survivor bias about becoming more conservative as you age
Anyone working with dates and times was cursed in a past life. Timezones are a pain to work with. Daylight savings sucks. Some countries change daylight savings at different times. Some countries change timezones sometimes. Go further back and some countries had their own leap days. Different calendars don’t form neat cycles and must be manually synchronized every few years. Did you know Easter, for about 300 years, needed to be announced by the Pope each year because it was a lunar holiday based on a Jewish calendar but the Christians followed a different one? Also, every now and again we throw a leap second into the computers because the Earth’s rotation is gradually slowing down and 365/366 days isn’t quite precise enough anyways.