It's sometimes embarrassing not to have an immediate, good answer to a completely predictable question. What's an example of a website or product with good usability?
The classic response to many questions about usability, including this one, is "it depends." To illustrate the point, consider the pictured hands-free bathroom sink faucet. (Credit to Donald Norman's Design of Everyday Things for this example.) You may find this appliance in public buildings, and in that setting it does its job well. It's quick and easy for hand-washers to use, and its design saves water. Since there are no controls to touch with soapy hands, the design also minimizes the need for cleaning.
However, just try brushing your teeth with one, and you'll see why you wouldn't want this faucet at home. Holding your toothbrush under the faucet doesn't always turn the water on. Not only is the on-off control optimized for washing one's hands, so is the water temperature and rate of flow. Neither can be changed. As a result, this faucet is highly usable for washing your hands but poor at other tasks, such as washing dishes or getting a cool drink of water.
So "it depends" is a perfectly valid response to the example question. It even can lead to a teachable moment, an opportunity to show people how usability depends on knowing the needs of your audience. Nevertheless, I find this answer embarrassing because it smacks of hypocrisy. It's much easier to pick on a design than it is to create or improve on one. This critic problem is true in many fields, of course.
