I have lived through GUI changes with products, some minor, some major. Most have been an improvement. Office was not.

Here's GUI changes that I liked immediately:

Jamstix 1.x to 2.x (huge improvement and huge makeover)

Matlab (don't remember the version but when they went from command line only to some kind of GUI was a great leap forward)

GUI change that took me a bit but still liked it in the end after a few hours of use:
Tracktion 2.x to Traction 3.x

With MSOffice 2007, not only did they change the GUI, they changed quite a bit of VBA underneath and programs that I had written in previous versions of VBA required some changes. That was REALLY irritating.

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