There is a bit of a learning curve. I guess Hypercard and Lotus Notes would have be the easiest to learn. Maybe throw Excel in also since it can be used (or abused) for a lot of things.
Emacs never really got the "popular test" that something like Hypercard did at a very important time in the adoption of personal computing, probably because most normal personal computer users didn't have access to it. But what we do see from the Hypercard days is a completely different -- even opposite -- relationship of average people to their computing media than we have today. It's both a compelling demonstration of what's possible and what's been lost
