> You don't press a button to sit in your chair, you just sit on it because you know how to do it. A microwave oven might be a better example, since a chair is

> You don't press a button to sit in your chair, you just sit on it because you know how to do it. A microwave oven might be a better example, since a chair is inert. On a microwave one has to have discoverable controls. Imagine if everything was just flat with the fascia, looking no different in presentation to the maker's logo. It might say 'Cooking power: 80%' with no indication of how to adjust. Apparently, though, if you press on the word 'power' repeatedly you can change it! I don't think we'd accept that.