After being used to using the wonderful "Sinclair Basic" for so many years since 1980, the thing that really impressed me was the introduction of the Microsoft Windows Graphical User Interface (GUI).
Without all the additional stuff included in various Windows upgrades over time, I still appreciate the ease of navigating the Windows GUI system with the Keyboard and Mouse.
In the race for the GUI with Microsoft and Apple in the early PC days, Microsoft took over the lead with most PC builders and folks.
I'm still happily using my Windows 8.1, running in "Classical Shell Mode Display*", following Win 7 and XP!
It does what it says on the Tin!....

...!
Paul....

...!
*
http://www.classicshell.net/