You're the head of product at a services company in Madrid. You want more customers to choose the annual plan —better for them and for you— but few do. Your finance team proposes the usual move: cut the price. You've read enough behavioral economics to suspect that a good default and less friction would move far more people, more cheaply, than a price cut.
The situation
The classic model assumes rational consumers who respond to price. But real people decide with shortcuts: they pick whatever comes as the default, avoid friction, and anchor on how the options are presented. That's why a design change —setting the annual plan as the default, cutting the steps, reframing the comparison— usually moves far more behavior than a price cut, at almost no cost to margin.
Here's the trap, in two directions. If you assume rational consumers and only touch the price, you leave the most powerful lever on the table and sacrifice margin besides. But behavioral economics can also be misused: dark patterns —hidden fees, deliberate friction to cancel— boost the numbers short-term and destroy trust (and draw the regulator) long-term. The defensible use is the one Disney made with its FastPass, or a good savings default: design for how people actually decide, aligned with what they truly want. Reduce friction on the good; don't hide the trap in the bad.