[jordanlev]

Yes, it's a bit dated (check out those screenshots!)... but the fundamental concepts are still valid. He's trying to explain that you should make programs behave as the user would expect them to -- but it's up to you as the developer to use your judgement to know what the common expectations of the time and platform are.

[noir_lord]

I was taught this as "The Principle of Least Surprise" or do the thing that causes the least surprise.

Where it gets tricky is that as programmers we are also power users and our mental model of what we expect to happen and what a user expects to happen diverge, I try to have empathy for the user.

One of my tricks is to imagine what my mum would expect to happen (not because she's a woman, it's not a sexism thing I hasten to add) but because she's a 60yo woman who didn't start using a computer until she was in her 40's and is slightly wary of them still.

If it passes the mum test then I know I'm on the right track.