The main takeaway from chapter 9 was that you can never do user testing too early or too often. Even if you haven't started any actual design work you can test competitors' products or those with similar designs and elements. User testing used to be much more complicated and expensive, so that still puts a lot of people off the idea, but with modern technology it's much easier, quicker, and cheaper to get useful feedback. Even if the participants aren't your 'expected users,' their feedback is still helpful as you should try not to alienate anyone by making things too specific. If anyone can use it, that includes your target audience. Chapter 11 goes more into avoiding things that can cause frustration and 'deplete your goodwill reservoir,' things like hiding information, being too demanding with inputs, and cluttering it too much happy talk. Other things can restore goodwill, like displaying the needed info cleanly and clearly, allowing for simple c...