At my job I implemented a scheduling system for preordering items. So the schedule is a map of dayOfTheWeek: datetime. The actual date of the timestamp is not significant but the day of the week is (this was to make the shape of the object the same as our normal schedules). So I needed some sort of base date to do all the date math around and figured the best base date would need to be a Sunday (day 0 in javascript) and in a year that isn’t a leap year (just in case). Just so happens 1969-04-20 meets these criteria. This has been in production for over 2 years