One of the most challenging obstacles salespeople, business owners and professionals have to overcome is our own assumptions. Our assumptions determine our behavior: Bad assumptions lead to bad behavior, which leads to lost sales.

Here are six of the most dangerous assumptions:

1. “They’re not a buyer.”
The guy in the t-shirt and faded jeans? He could be a millionaire.  The woman pushing the baby stroller? She could be a CEO. You never know. Buyers don’t need to impress you. You need to impress them—by always taking them seriously and being respectful.

2. “Buyers want to be left alone.”
Buyers don’t want to be hassled or pressured. They do want to be engaged, advised and assisted. They want to be made to feel welcomed, comfortable and confident. They want to be talked with, not at. They want to be served. When prospects are ignored, they feel unwanted and unappreciated. When that happens, they go somewhere else in search of better treatment.

3. “The man is the decision maker.”
Women control the checkbook in 80% of households. Even when they don’t, they often still have the final say. And that doesn’t count all the situations when the woman is the buyer and the man simply happens to be there. When talking with a couple, address both people equally.

4. “Buyers are ignorant.”
With access to virtually unlimited amounts of information, today’s buyers often know more about a particular product or service than the salesperson does. Further, they often know more about the competition than the salesperson does. Respect the prospect’s intelligence, experience and knowledge.

5. “The decision-maker is the only person who matters.”
While the decision-maker may make the final decision (hence the name), if you don’t have all or most of the influencers on your side, you’re dead meat. Influencers are the people whose opinions the decision-maker solicits before rendering said decision. They can include accountants, attorneys, IT people, managers, front-line workers, even the receptionist. Because they all have the power to make or break the sale, they’re all important.

6. “They’ll call when they’re ready.”
They might. Or they might get caught up in other issues and forget about you entirely. Or they might say yes to anther salesperson who follows up and asks for the order. Don’t risk it. Follow up consistently.

If your sales aren’t where you’d like them to be, check yourself and your sales team for these assumptions.  Odds are, you—and your team—are harboring one or more of them without even being aware of it. When you change your assumptions, you’ll change your results.

What other assumptions have you found are detrimental to sales?