Clayton Christensen, Author of Innovative Dilemma and How Will You Measure Your Life, speaks about how important it is to understand what 'Job' your product is trying to achieve, and the importance of speaking to your customers to find this out.
Your product could be being used for a very different reason to what you set out to achieve, and to what you are marketing it as. Watch this video to find out the real reason customers were purchasing early morning Milkshakes at McDonalds as one simple example.