Gathering customer insight helps you to validate your product is going in the right direction. You have to ensure you don't go too far before you check in with your customers. Otherwise you are probably creating 'waste' or at least guessing. How you collect customer insight will change depending on the status of your product and as your need for detail progresses. But, you will always be looking to tap into any kind of dialogue that checks your ideas, approach or features.

The thing that's often a mistake is to believe that (real or imagined) customers being positive about your ideas is the answer or 'validation'. Validation shouldn't automatically assume a positive response is the goal. I'd go further and say that it's better to have your audience destroy what you presumed to be a good route forward.

Why? Because this keeps the design process alive, it forces you to think and engage with a critique that might just cause you to make a leap into a new territory, it makes you think about why something isn't working and how to change it and test it again. While this appears masochistic, it's usually incredibly valuable since what you lose in the process can lead to a deeper understanding of the problem you're trying to solve.

Simply finding out that people like your ideas and accept your proposition may mean you stop thinking critically and that suggests your done, and done suggests finished. Nothing is finished, because your products should be vehicles for conversations with your customers. Unlike books, paintings or ads they live in a environment that continually grows and demands new or subtly shifting qualities.

So next time your product meets with a sour reception, just remember, it might be the thing that makes it sweet.