Wonderful consumer applications often will present the user features that create delight. Delight is one of the most important concepts to understand, and one of the least understood by engineers, especially in the software profession. Software engineers bathe themselves in objectivity, practicality and scientific analysis.

If it isn't measurable it simply isn't important.

Taken to an extreme, we get to the world of Linux, where the ideal text editors have cryptic memorized commands to simply navigate your document. Pressing 'j' and 'k' move your cursor up and down, and 'h' and 'l' move your cursor left and right. The reasoning for this? When you type, your hands are supposed to stay on the home keys. Since moving the cursor is something a user will do often, they map keys on the home row to movement so that the user does not have to move her hand away from the home row. Once a user becomes an expert at all of the cryptic commands, they become far more efficient at text editing than on any other editor.

The critics of Cover Flow in iTunes complain that it is superfluous, unnecessary, and an inefficient way of navigating through your library of music. Perhaps all of these things are true. But they are missing the point.

Cover Flow creates smiles.

There are little features that create delight for a user. In one of the first few posts on this blog, I described my experience unboxing my first iPod:

Well, finally it is in my hands, and I have to say that this is one of the coolest toys I have ever played with. If first impressions are everything this has won me over already. It is housed in the best packaging on any product ever that I've ever opened. It may sound silly, but opening the iPod box is really an experience. Everything slides open, folds open, fits perfectly, and is overall very slick. You can tell the packaging was really well thought out.

And there it is. If the experience of opening the box of a product gets someone giddy, something powerful is happening there. Human beings are emotional creatures, and emotions can override objectivity and practicality on a daily basis for everyone–except engineers.

Engineers, scientists and generally those in technical professions are trained out of style over substance, and instead are laser focused on metrics and objectivity. There is important for a few reasons, least of which is that you certainly hope that bridge builders care more about stability than aesthetics! As long as product designers are not killing their users, they should focus on the emotional effect of the product itself.

If users are delighted enough, they will actually overlook flaws in your product. I remember I debate I was having with coworkers over the iPod spin wheel thingy. They argued that it was impractical and impossible to hit exactly what you want in the UI. I argued vehemently, stating that it was possible with the right amount of practice. I exclaimed that I had been using iPods for years and could hit exactly what I wanted every time! So of course, I was challenged to prove myself. So I whipped out my iPod and did a demonstration. And as I bounced up and down trying to hit the menu item I was looking for, quickly my smug look faded away as one appeared on my colleague's face.

This is not an isolated incident. When enough delight is built into a customer's experience, they will march with you until the end of time. Delight creates emotional experiences. And once emotion is evoked between a user and a product, only then can a user fall in love.