Design serves two primary roles--functional and emotional.

The separation between these two roles used to be distinct. Engineers dealt with the product's functional design, primarily the backend aspects. Product designers focused on crafting the desired emotional outcome associated with the product's attractiveness features, the customer facing aspects.

Technological advances have narrowed the gaps between the functional and the emotional to the point that they complement each other, and to the degree that they are sometimes difficult to differentiate. As long as the distinction between the roles of engineers and designers was maintained, there were negative implications on the product's user experience.

Let's use "buttons" as an example:

• Have you ever pressed a button on a device without knowing what the button does, or knowing what to expect?
• Have you ever wondered if a button indicates an On or Off state?
• Have you ever searched, unsuccessfully, for a button to turn the device on or off?

It is highly likely that you had such experiences with various products, such as home appliances, projectors, remote controls, digital watches, and many others. Why?

Products don't need buttons, but people do. Buttons allow the user to trigger an action that makes the product perform a certain function. The experience of using the product truly depends on the lowly button. The clarity of its position, label, or purpose can determine whether the overall experience would be satisfying or frustrating.

Buttons are everywhere. Their potential to unify engagement and delight for the user cannot be underestimated, yet the design of buttons is often neglected. Ironically, one of the primary reasons for this is designers' insistence on "clean" and minimalist designs, which end up being obscure and less functional.

Physical and digital buttons co-exist on numerous products, and designers have many options for buttons, such as shape, position, material, color, texture, and labels.

In physical products, little thought was given in the past to the experiential aspect of buttons. When button design was considered, the focus typically was on the on-off switch, which was relegated to the mundane and functional. Shapes used to be curiously limited to circles or squares, with the possible exception of buttons on children's toys. Since buttons equated functionality, little consideration has been given to the usability of button overload:

Increasingly, however, designers are re-imagining the use of buttons and their contributions to rich user experiences. These days, almost anything can be designed to function as a button, as the surfaces of products and screens can be engineered to respond to a user's voice, touch, gesture, or motion. As part of the re-imagining process, designers simplify the product experience by reducing the number of buttons with which users need to interact. Fewer buttons--sometimes just a single one--perform multiple functions in response to different types of user input, such as a single tap, double tap, and so on. Fewer buttons allow for streamlined and elegant designs, and the buttons themselves are designed to be points of engagement--glowing, pulsing, changing colors, and other visual effects.

In the physical world, we don't think much about the experiential dimension of buttons until we notice they exist. For example, in the case of the car ignition experience, consider the following image:

Until recently, the experience of many drivers included the rattling sound of a heavy keychain loaded with an assortment of keys, the car's remote, a charm or a small utility item, all hanging off the ring that also held the car key placed in the ignition switch. The ignition key is being replaced by a large single button. The following are several benefits of this transition:

• The old keys had a double function--they unlocked the car doors, and turned on the engine. Drivers who forgot the key in the ignition, sometimes locked themselves out, requiring assistance to break into the car, if a spare key was not around. This cannot happen with the electronic button, since the doors are controlled by a fob that the driver can keep in their pocket.
• Turning the car on and off feels more like interacting with an appliance or a personal device. It is very easy. The old key had three states, and the driver had to turn the key all the way to turn the car on or off. Not a difficult operation, but sometimes drivers had to try multiple times, or the key got stuck.
• When pressing the new type of ignition button on or off, it omits a pleasant and welcoming lighting and sound effect that greets the driver and adds to a sense of anticipation and comfort before the start of the trip, even if it is only to the grocery store.

Expressions such as "one click away" or "in a click of a button" represent a promise of ease and speed. Buttons have always held this promise, but as they became more common, we stopped noticing them. Like the example of the car ignition button that transforms a mundane action into a pleasant audio-visual experience, buttons on physical and digital products provide renewed opportunities to engage the user, and be fun.

And yet, just as car keys and keys in general, are slowly giving way to biometric authentication, there is also a trend of transitioning interaction and control of products from human manual actions to autonomic, automatic, self-learning devices that anticipate user needs.

This applications can offer a great user experience, but do you know what the companies behind such products do with the enormous quantities of intimate information they constantly collect from their individual users? The long-term risks for misuse cannot be ignored.

Is it ethical to design great experiences for unhealthy or dangerous products such as junk food, questionable food supplements, pornographic websites, or websites for extreme fundamentalist groups, firearms and other weapons? Like any other person, when it comes to ethical decisions, each designer decides on their zone of comfort, so we will leave it at that.