The VisiCalc story blew my mind here. It calculated everything from left to right over and over?

Around 2000 we had to make a spreadsheet in Java as an assignment in an introductory programming class. That it would be calculated in "demand-order" was such an obvious requirement it wasn't even mentioned in the assignment. This says something about what modern tools and languages does (Not that Java and Swing feels all that modern any more). Because they surely understood the problem way better than introductory programming students 20 years later.