I do believe that users are the most important part of a project. Really. They can provide you useful feedback, great ideas and suggestions on what can make your product better. Unfortunately the previous sentence only apply to few users.
In my experience, users are only interested to their own small needs. They don't care about your product but just to solve the problem they have today. More than once it happened to me that a customer asked me a change on a software to solve an urgent issue and few days later he wanted me to roll back the modification.
Having the development of your product driven only by users' requests is the fastest way to go crazy.
Feedback and hints are important but must be taken with a grain of salt. Don't abdicate the development of your product to users and customers.
A similar situation apply to tests. I've heard sometimes "The customer will do the tests." It may be OK if we are speaking about a small customization. But in all other cases, the result will be terrible. A user will test only the three or four functions that uses the most and, if something is not working properly, it's probable that he will find a quick workaround instead of spending half of an hour on the phone with your customer service. And even if they spend some time to report the issues to you, it's very likely that most of the messages would be like those reported in this page.
Again, users are not interested in your product. They only want a tool to solve their own problems and you should just thank them because your software has been elected. But don't ask them to do your job.