Nowadays, mobile apps often resemble amusement parks – dynamic, loud, and engaging. Designed so that something’s always happening. In a world where user attention is a scarce resource, emotions have become the new currency. They are what determine whether the user will return and how they’ll remember your product.

Some apps have truly mastered this art. Take Duolingo, for instance, which transforms language learning into a game filled with daily tension. Will you open the app today to keep your streak alive, or lose your hard-earned points? The green owl celebrates your wins, but it can also give you a look of pure disappointment. And rest assured, it won’t hesitate to remind you with a push notification.

The Temu app plays a different set of cards – you’ll find reward coupons for activity, limited-time lotteries, and “today only” deals. Add to that a set of micro-interactions that, if they had a sound, would resemble the jingle of coins in a casino.

There’s no shortage of examples on the Polish market either – Biedronka’s Shakeomat has already become a pop culture phenomenon. One hundred million shakes per month is an impressive number, showcasing the power of enhancing users’ daily lives by combining micro-interactions with discounts.

When UX meets behavioral economics

These examples share one common denominator: they were intentionally designed by us, Product Designers. After all, we mustn’t forget that the users of digital products are people, and universal psychological mechanisms affect them. These mechanisms even have a name – behavioral economics.

Duolingo is a prime example of the hooked model described by Nir Eyal: it starts with a trigger (a push notification). This leads to user action (completing a lesson), which is rewarded (with points). All of this is built around the key element of the model – investment (time).

Our brain is also influenced by loss aversion – losing a streak hurts more than gaining one feels good. On top of that, the entire user experience is wrapped in gamification mechanics that activate the brain’s reward center. All designed to bring you back to the app again and again.

At Temu, emotions are built around scarcity and time pressure. The message “12 people are viewing this product” isn’t just information – it’s a decision accelerator designed to shorten the gap between desire and purchase. This taps into the scarcity effect, a key principle of behavioral economics: the less there is of something, the more we want it, even if we didn’t need it before. That’s why messages like “Only 3 left in stock” or “Offer ends at midnight” so effectively speed up decisions. The brain reacts to scarcity, fearing it might miss out on an opportunity.

The Biedronka Shakeomat is a classic example of the IKEA effect. We value furniture more when we assemble it ourselves. Similarly, we appreciate rewards – even just a few cents – more if we’ve put in even minimal effort to earn them. It’s not about what you get but that you have to do something. Shaking your phone doesn’t change the reward’s value, but it changes how we perceive it.

Designing responsibly

Observing the design industry, it’s clear a paradigm shift is underway. UX is moving away from asking, “Will the user understand?” to “What will the user feel – and is that what we want them to feel?”

Designers are increasingly like emotion operators. They set the pace, control the lights, and decide when to start and stop. Their role determines whether the user experiences an emotional ride – and if they’ll want to come back for more.

But with this power comes responsibility and ethics. Designing emotions isn’t just about boosting conversions; it’s a tool that can overwhelm, distract, or even addict. And today – in a world of growing digital mindfulness – people are more aware of how products engage them and the methods used.

Conscious use of these mechanisms is the essence of a mature design process. When used wisely, emotions can significantly increase business value – but only if the human element isn’t lost along the way.

If we turn our products into amusement parks, let’s make sure users leave satisfied – not queasy.