The first 'PC' I had any real exposure to was a Mac in 1984. I was a film and video person with little computing background (one intro to programming class, in Pascal). The Mac made perfect sense to me -- moving pictures of documents and folders around on a desktop, drawing things, painting things. When I later saw what most computers were used for, and what their UIs were like (this is the mid-1980s), I was dumbstruck. Text and numbers on black or green backgrounds, arcane text commands, etc.
I started working in IT not much later and pushed every project I worked on (even terminal-based applications for beverage manufacturing and the like) in the direction of the "right" paradigm -- what I learned about what computing could and should be, from the Mac. Even today, when we've moved from the Iron Age to the Iphone Age, I still find myself thinking about UIs with the 1984 Mac OS as my reference point.