The devil is in the detail. That old saying alluding to a mysterious element, hidden behind something seemingly simple, has a particular resonance for designers. In some of the best product design, the tiniest of design details elevate a good piece of design to something great. Yet when it comes to digital design, all too often this opportunity is missed.

It occasionally exists – consider Insane Mode, which Tesla introduced on the new digital console for its upgraded dual-motor Model S a few years back in the form of a button you toggle that quickly accelerated the car to between 60 and 70 mph in just a few wild seconds. Or the ‘A bit more’ button Breville introduced to its toasters, which gave every user the opportunity to personalise their toast experience according to individual taste.

Both add to the user experience something a little bit exciting and surprising, fun and quirky. Each taps into the widely accepted wisdom that 80% of the decisions we make on a day to day basis – including purchasing decisions – are based on emotion, while logic drives the rest.

These aren’t just whimsical foibles of brand personality that slipped through the net. Rather, they are conscious manifestations of brands’ growing understanding of human psychology, which has led to the waning of the rationality paradigm and the ascent of emotional connectivity.