Relevant “Bill Gates vs Excel dates” story from 1992 [1]:
> “I don’t know, you guys,” Bill said, “Is anyone really looking into all the details of how to do this? Like, all those date and time functions. Excel has so many date and time functions. Is Basic going to have the same functions? Will they all work the same way?”
> “Yes,” I said, “except for January and February, 1900.”
> The WEEKDAY function returns incorrect values for dates before March 1, 1900. Because most users do not use dates before March 1, 1900, this problem is rare.
> “I don’t know, you guys,” Bill said, “Is anyone really looking into all the details of how to do this? Like, all those date and time functions. Excel has so many date and time functions. Is Basic going to have the same functions? Will they all work the same way?”
> “Yes,” I said, “except for January and February, 1900.”
[1] https://www.joelonsoftware.com/2006/06/16/my-first-billg-rev...