In the Harry Potter books, the ethical wizards have agreed to leave the Muggles alone and not do magic tricks on them. It seems that computer wizards have something to learn from Harry Potter, because they often use their power in ways that are harmful to regular people.
I typically argue against poor Internet usability because it reduces a company's ability to generate business value from its website. Bad customer service equals fewer customers. However, the bigger picture is even worse: Every page that doesn't conform to expected behavior and design conventions undermines users' ability to build a conceptual model of the Web, and thus reduces their ability to use other sites with ease, confidence, and pleasure. Designers who inflict poor usability on the world and its Muggles are wicked wizards indeed.
This is fundamentally wrong in several ways.
First, inconvenience and evil are not indistinguishable. Poor usability is chiefly a matter of inconvenience: making things take a little longer, making users take unnecessary steps. It's not nice, but there are worse things. Let's keep some perspective.
More substantially, conforming to 'expected behavior' is not the mark of a varied, rich, and sophisticated intellectual life. The urge to insist that expressive media conform to the imperatives of expectation and efficiency has had a sorry history in the past century or so. Usability is nice, but conformity is conformity.
Finally, to regard users as Muggles is, I think, fundamentally wrong. In fact, Rowling's "ethical" wizards are, if you take them seriously, mere cowards. Why do they hide magic from the Muggles? Yes, some Muggles are small-minded, mean, ignorant, and superstitious: does this relieve the ethical wizard from an obligation to treat muggles with decent respect? Where were the ethical Wizards in 1938-45? What are they doing about AIDS, global warming, hunger?
Equating users and Muggles is a symptom of believing yourself to be a programmer. If you believe this, you are mistaken: Nobody is a programmer. There are people who know how to program, just as there are people who know how to write, or to read French. There are no non-programmers; there are only people who have gaps in their education.
Make me think, please! If you're going to talk to me, surprise me, delight me -- you've got to make me think. That means, from time to time, you want to astonish, inconvenience, surprise, shock, and delight. There's a time for conforming, and mastering conformity is a vital skill, but let's not pretend that conformity has a patent on virtue.