Here is a site that is not only useful, it is also somewhat amusing. The basic concept being conveyed is why learn from your own mistakes when you can learn from someone else's? Any type of engineer, student, or professional should know the difference between a bad design versus a good one. This site has a long list of bad designs, and new ones are added regularly. The material is maintained by a usability engineer, which means he obviously knows a lot about the topic. Some examples include a stapler, a paper towel dispenser, and a shower faucet. They might not make sense right now, but look over the site. You should soon realize the importance of a good design.