Kathy Sierra at Creating Passionate Users writes about how Good usability is like “water flowing downhill”:
I’ve talked about this many times before; my horse trainer’s mantra is, “Make the right things easy and the wrong things hard” – but the opposite is everywhere. It’s ridiculously easy for me to screw up the settings on my digital devices. The API methods that intuivitely feel right turn out to be dead wrong. I click the button I think will do X, and instead I get… WTF?