We’ve all encountered a door like this. It has a large, inviting handle that practically begs to be pulled. So you pull. Nothing happens. You pull harder, feel a slight flush of embarrassment, and then notice the tiny sign that says PUSH!!! The shop owner has watched this happen hundreds of times. At some point they stuck up the sign, then a bigger sign, then perhaps an arrow. Customers still pull. It’s tempting to conclude that people simply don’t pay attention. But the more interesting explanation is that the door is lying to them. The handle says “pull”. The sign says “push”. And when design and instructions disagree, people believe the design almost every time. Here’s what Im saying: Affordance: What an object allows someone to do. A door can be pushed or pulled, depending on its mechanism. Signifier: The visual clue that tells someone what action to take. A large vertical handle suggests pulling, while a flat plate suggests pushing. Poor design: When the physical design suggests one action, but the correct action is something else. Human-centred design: Designing around how people naturally think, interpret information and behave, rather than expecting them to follow instructions that contradict their instincts. It’s tempting to conclude that people simply don’t pay attention. But the more interesting explanation is that the door is lying to them. The handle says “pull”. The sign says “push”. When design and instructions disagree, people almost always believe the design. That small, everyday irritation sits at the heart of a big idea about how people think, and it has very little to do with doors. Every business has its own version: the form that confuses, the price list that gets misread, the button nobody clicks—understanding why can change how you see your customers’ “mistakes”. That’s why the PUSH sign rarely solves the problem. Most of our everyday actions happen on autopilot, guided by learned patterns. By the time a customer’s conscious mind reads the sign, their hand has already pulled the handle. As one summary of Norman’s work puts it, when affordances and signifiers are used well, “you shouldn’t need a sign on a door,” because the design itself does the talking. Norman is careful not to treat signs as useless. Labels are a valuable form of what he calls knowledge in the world, information placed where people need it so they don’t have to remember it. But when a design needs a sign to correct what it’s visibly suggesting, the sign is a symptom. The fix is to make the design say the right thing in the first place. When customers keep making the same mistake, perhaps it’s time to question the design, not the customer. Mental Models and Signifiers The confusing door has a name in design circles: a Norman door, after Don Norman, the cognitive scientist whose book The Design of Everyday Things has shaped how designers think for more than three decades. Norman argues that objects communicate with us whether their makers intend it or not. He describes several ideas that explain why:  A signifier is any cue that tells people what to do and where to do it. A flat plate on a door signals “push”. A vertical handle signals “pull”. People read these cues almost instantly and mostly without thinking. Human-centred design: Designing around how people naturally think, interpret information and behave, rather than expecting them to follow instructions that contradict their instincts. A mental model is a person’s working understanding of how something behaves. When the signals a design gives match the mental model a person brings, using it feels effortless. When they clash, people hesitate, guess and make mistakes. That’s why the PUSH sign rarely solves the problem. Most of our everyday actions happen on autopilot, guided by learned patterns. By the time a customer’s conscious mind reads the sign, their hand has already pulled the handle. As one summary of Norman’s work puts it, when affordances and signifiers are used well, “you shouldn’t need a sign on a door,” because the design itself does the talking. Norman is careful not to treat signs as useless. Labels are a valuable form of what he calls knowledge in the world, information placed where people need it so they don’t have to remember it. But when a design needs a sign to correct what it’s visibly suggesting, the sign is a symptom. The fix is to make the design say the right thing in the first place. “A brilliant solution to the wrong problem can be worse than no solution at all: solve the correct problem.” — Don Norman, The Design of Everyday Things Blame the design, not the customer Norman makes a further point that business owners will recognise from the other side of the counter. When something goes wrong, people tend to blame themselves. They assume they’re being slow or silly, apologise, and try again. After enough failures, they may stop trying altogether. His response is one of the most useful ideas in design: what looks like human error is usually a sign of poor design. He distinguishes between two kinds of error. A slip happens when someone knows what they want to do, but their action goes astray, like clicking the wrong one of two identical buttons placed side by side. A mistake happens when their understanding is wrong, often because the design gave them a misleading picture of how things work. Both can be reduced by design: slips through clearer layouts and easy ways to undo, mistakes through better signals about what’s going on. Search Google to understand their problem and possible solutions Ask AI platforms such as ChatGPT or Claude for answers and recommendations Read reviews to understand other customers’ experiences Compare competitors on pricing, expertise, services, and reputation Explore social media to see how a business communicates and what others are saying Read case studies for proof that a business can actually deliver All of this means that a significant part of the buying journey