Imagine typing some text into a dialog. The standard actions are:
What could be simpler? This sequence is shown in the following picture.
But notice how, in the last picture, the pointer has disappeared! This is because whenever you start to type on the Mac OS, the machine obscures the pointer. When you next need it, you grab the mouse and the act of moving the mouse displays the pointer and you're away. But while you're typing it remains hidden, to avoid it getting in the way of you seeing what you type.
I discovered this feature of the Mac the first time I used an Amiga and it didn't do this. Consequently, I'd go to type into a field and be unable to see what I was typing because the bloody pointer was in the way. I then went back to the Mac to see why the same thing hadn't annoyed me on it as well, and discovered this particular human interface subtlety.
Curiously enough, this month (August 1995) I went to help a friend with their Windows machine (I normally don't do Windows) and found that it still didn't have this trivial feature that the Mac has had since Day 1. Sigh. I wonder whether Windows 95 gets it right? [Reports from the field indicate that it does not. -- Quinn]