Over many years in sales, I have noticed something interesting. The harder you try to come across as the expert who knows everything, the less credible you often become. People rarely trust those who always have an answer. They trust those who are honest enough to admit when they do not know. Paradoxically, it is often the ability to say “I need to check that” that reveals who truly understands their field.
Credibility Is Not About Knowing Everything
In sales meetings, particularly in the video conferencing industry, a field I know very well, I have sometimes done the opposite of what people associate with honesty: I lied. I said I did not know and chose not to answer immediately. Not because I wanted to mislead anyone, but because I knew that answers that come too quickly can sometimes seem less credible. People do not believe you because you know everything. They believe you because you are genuine. So instead, I would send the answer by email the following day, “after I had looked into it.”
I also have a friend who always has an answer. No matter what we discuss, the response comes immediately. Never a simple “I don’t know.” And although I like this person very much, I quickly lose interest when conversations become like that. Not because the answers are necessarily wrong, but because there is no room for curiosity. When someone always needs to have an answer, the conversation becomes less about exploring ideas and more about reaching conclusions. The goal shifts from learning something new to having the last word.
Research actually shows that people are perceived as more credible when they are willing to admit uncertainty. A study from Harvard Business School found that people who admit they do not know the answer are often seen as both smarter and more trustworthy than those who always claim to be right. (“The ‘I Don’t Know’ Effect”, Harvard Business Review, 2020.)
Product Knowledge Is Not About Knowing Everything
When you truly know your product, it shows. You speak with confidence, not because you have memorized a sales pitch, but because you understand what you are selling, who it is for, and the value it creates. That confidence means you do not have to pretend you know everything.
Product knowledge is not about having all the answers. It is about understanding the product well enough to explain it clearly, answer honestly, and know where to find the information when you need it. That is why “I need to check that” is often a sign of competence, not a lack of it.
According to social psychology, credibility is not just about knowledge. It is also about authenticity, the alignment between what you say and what you genuinely believe. When you speak with calm confidence, people pick up on that sense of security through your body language and tone of voice, a phenomenon known as emotional contagion.
Why Honesty Works
Research in social psychology shows that credibility is about much more than knowledge alone. We also evaluate honesty, integrity, and whether a person seems genuine. That is why a sincere “I don’t know, but I will find out” can strengthen trust more than a quick but uncertain answer.
Most of us have met people who seem too perfect. They have an answer for everything, never hesitate, and always appear confident. Paradoxically, this can make them seem less trustworthy. After all, we know that nobody can know everything.
When someone openly admits uncertainty or takes time to investigate something more thoroughly, they often come across as more genuine. It creates the impression that they care about finding the right answer rather than simply appearing knowledgeable.
True Expertise Is About Finding Answers
People who always seem to have the perfect answer and never hesitate often appear less credible. It is like talking to a billboard: impressive on the surface, but lacking depth. People are not looking for perfection. They want to connect with someone who understands them.
Great customer conversations, and strong relationships in general, are not about being flawless. They are about being honest, confident, and genuinely interested in solving the problem. In human interactions, it is not knowledge alone that matters, but how you use it.
Psychologists call this the Pratfall Effect, first identified by social psychologist Elliot Aronson in the 1960s. It shows that people often like others more when they make small mistakes because it makes them seem more human and relatable.
“The most trustworthy people are rarely those who know everything. They are the ones who are willing to admit what they do not know.”
As this website probably reveals, I know a lot about a lot of things. That does not mean I know everything, or that I remember everything in detail. When I write about a topic, I usually start with knowledge, experience, and observations I have accumulated over the years. Then I go deeper, reading research, checking sources, and exploring new perspectives. Quite often, this confirms what I have already experienced in practice. Other times, I discover new nuances and insights. That is how knowledge develops, layer by layer. Product knowledge is therefore not about knowing everything by heart. It is about understanding your field well enough to know both what you know and where to find the rest.
Our brains are not designed to remember everything. They are designed to recognize patterns and retrieve information when needed. That is why true expertise is less about memorizing every answer and more about knowing where to find it. This idea is supported by research in cognitive psychology and the “extended mind” theory, including the work of Clark & Chalmers (1998).
