I think you should go with Vaniver's idea. (Edit: Vaniver now has multiple ideas up. I mean the one about giving orders to malicious idiots. Completely off-topic: that's also a useful way to explain tasks to people with Asperger's Syndrome or other neurological oddities that cause executive dysfunction.)

I also think this reminds me of something (fiction) writers talk about a lot: they've hit on the way people won't sympathize with "a billion people died/starved/were tortured/experienced dust specks in their eyes" but will sympathize with "Alice was mobbed by dust specks and blinded" and will sympathize even better if you give some specific details about how it felt. And then they go on to talk about how to make Alice someone the reader cares about and how to craft sentences and other stuff that's relevant to them but irrelevant here.

But maybe something like making up a character and talking someone through xyr experience using the product step by step, in the kind of detail a novelist would use to describe the climactic fight scene.

Another idea that occurred to me is some sort of exercise where two people would pair up. One would have to do a novel task or navigate some kind of obstacle course blindfolded and the other would have to give directions. They wouldn't be able to get away with "turn right at the statue" but would instead have to give directions like "turn right at the big smooth stone thing" and... I guess if you were doing something like that, you'd want to give the non-blindfolded partner a picture or map and NOT let them see the one doing the actual task. Otherwise they'd just be able to say "okay, turn right now... turn left... turn left again..." and that would defeat the purpose.