Fadell shared three main secrets of finding these "invisible problems."
1) Look broader at the bigger picture to see what steps are involved in a product. Examine which steps, or boxes, are necessary and which ones can be improved.
2) Look closer at the the tiny details and see which ones are important.
3) Think younger when examining problems. Why? Younger people have not been around as long to be exposed to the status-quo; therefore, when they run into problems, they sometimes find a better way of doing things.
Fadell also shares an anecdote about Steve Jobs' passions to see the product through the eyes of the customer. Jobs pushed employees to stay focused on the small details of each products so that for new customers, the products would work right out of the box -- Jobs called it "staying beginners."
Fadell then shares the example of purchasing an item for the first time and excitingly opening the box only to notice a sticker saying "charge before use." Jobs and Fadell took note of this minor nuisance and as a result, increased the amount of time the iPods were tested at factories so they would arrive to customer charged.
You can watch the entire video below, but the story about iPod and Steve Jobs begins around 6:30