In fact, I have basically no respect for those who discount it.
You probably can code circles around me. But in the end, the customer or user only sees the interface.
Actually you've hit on a major problem of programers that we don't like to talk about (well, except me, obviously..). The thing is, GUI design is a complex art, one that takes a long time to learn to do well, so its hard to be good both at visual interfaces and the often very complex code that they control.
I know this from my own work. I'm a pretty good coder (gosh, how modest of me). I can write code to just about anything, and charge a pretty penny to do so, but my ability to code a user interface is rather poor. Sure I know all the theory, but there's something extra you need, that 'eye for the visually pleasing' thats hard to cultivate unless user interfaces are what you do all the time.
I've used plenty of applications where the guy who wrote the backend code also coded the gui, and as a rule the gui is somewhat lacking. This is't just restricted to single coder projects, it also occurs when a project is full of able back end coders, and they build the gui to suit their own level of ability to use the code.
You can see this if you use Emacs. Nice though that software is in features, the interface is godawful, and actively prevents anyone new to computer usage or programing from using it.