Simplicity takes effort– genius, even. The average programmer seems to produce UI designs that are almost willfully bad. I was trying to use the stove at my mother’s house a couple weeks ago. It was a new one, and instead of physical knobs it had buttons and an LED display. I tried pressing some buttons I thought would cause it to get hot, and you know what it said? “Err.” Not even “Error.” “Err.” You can’t just say “Err” to the user of a stove. You should design the UI so that errors are impossible. And the boneheads who designed this stove even had an example of such a UI to work from: the old one.— Paul Graham