Dan’s Data:

If a developer doesn’t spend quite a lot of time on getting a graphical interface right, this is the sort of hideous disaster that’s likely to result. To avoid it, developers often find they need to make at least some effort to fight the good fight via usability testing; even if you spend months on assembling an interface that looks good to you, it may not work very well for normal users.

A great look at why knowing command-line interfaces is still so important today.