Reading Lidwell, Holden, and Butler’s excellent Universal principles of design, I noticed one that isn’t enunciated: being kind to your users. The authors of the 1662 the Book of Common Prayer clearly thought this was an important principle of design, as evidenced by these two examples, from ‘The visitation of the sick’ and ‘Prayers for use at sea’:
The very sick get spared the lengthy sermonizing, and those in peril on the sea are able to make their peace with their maker – quickly.