A fantastic blog entry on 37Signals’ Signal vs. Noise explores the complexity of creating effective, simple user experiences:
Sometimes there’s a lot more to simple than meets the eye. To the customer, this is just a few obvious words in a small box. But really, that’s the point.
The sheer amount of work that can go into something as trivial as creating two lines of helper text is sometimes frightening. People who don’t do UI design typically look at the work I do and pooh-pooh it for “wasting huge amounts of time on a few measly pixels,” but ultimately it’s much more than that. Effective and clean user interfaces feel better to use, and make you far happier when you’re using them. They feel light and responsive, and (ideally) you might even forget that they’re there. That’s the ethos I think 37Signals has, and that never ceases to impress me.