There are two threads that run through the examples:

  1. Kindness and respect – My grandfather was a highly intelligent district judge, but he could not work a radio or toast a piece of bread. I design with him in mind: I have the utmost respect for the person who will be engaging with my designs, and I assume that they are an expert at something, but I assume nothing about their ability to parlay that knowledge into an immediate understanding of my design decisions.
  2. Usability over elegance (should the two conflict) – Usability and elegance are not mutually exclusive. Nonetheless, times do arise when a move toward clean design will compromise usability and vice versa. In such cases, I try to err on the side of usability. Better a person immediately forgets about their interactions with your product than to have them remembering how pretty it was but how impossible it was to use.