(Until Microsoft had actively started fracking it up, sometime around Windows Vista) just like a Roman citizen landing up in any town of the Empire, one would be able to effectively and consistently navigate around, using both keyboard and mouse across most Windows applications. Everything worked in a boring, predictable way. Everything used standard API that provided the whole spectrum of UI capabilities.
With Linux, unfortunately, this was never considered ideal and instead we have a zoo of different paradigms and technologies (plus intense politicking of UI development). Which means, when something happens to work as expected without excessive ServerFault/ChatGPT trawling and config/gconf/dbus wizardry, it feels like a sheer delight and an exception rather than a rule.