I have just given my annual lectures to some postgraduate students about what it’s like doing usability in the real world (i.e. the world where you can’t spend three months redesigning the perfect interface to a toaster).
And one of the issues I cover is why it seems to be so difficult to design usable products. It must be difficult - there are lots of clever designers and few really usable products.
I have recently returned from an international standards meeting in Washington (and that is a story in itself – I nearly had to fly without my laptop and Treo – aargh!) where we were discussing the revision of the human centred design standard ISO 13407.