Good craftspeople want to understand the world in which their product will be used before building it. We have the amazing power to create things, and it's easy to fall into the trap of building things that appeal to us as creators, instead of things that will appeal to our customers. There's no way to know how biased you are without working through usability engineering and other forms of customer feedback. You must spend time with users throughout the product cycle, repeatedly refreshing the team perspective on what you're building and for whom. There is a fundamental difference in how technologists and true designers approach making products.
Technical people tend to start with technologies.
We take teams of developers, build a technology, and then shoehorn a user interface and a user experience onto the framework dictated by the technology. This guarantees that the user experience will be a poor compromise. The product won't be designed for use, it will be designed as a ship vehicle for a package of technologies. A good craftsperson in any trade understands that people will consume their work, and every decision is made with that type of person in mind. Software or Web development is no different.