Years ago I noticed that when I was hungry and tired, I would notice just how much bad design got in the way of completing a task. Things that I would work arou

Years ago I noticed that when I was hungry and tired, I would notice just how much bad design got in the way of completing a task. Things that I would work around easily when I was well-rested and sated all of a sudden became incredibly frustrating. Unclear instructions, or buttons that were hard to find, or error messages that were inscrutable suddenly became very obvious. I posited that it would be an interesting user test to have someone who was in an irritable mood try to use your product. I've never actually done this, and I still think it would generate interesting feedback.