Back in 1983, Hollywood film producer Peter Guber had a brilliant idea for a box office hit. His idea was to create a snarky, witty who-done-it murder mystery film based on the board game, Clue.

Clue (the movie) quickly became a cult classic when it was released on video, but against all predictions it was a box office flop — grossing $14,643,997, just shy of its $15-million dollar production budget. The film’s lackluster ticket sales were due mainly to a marketing gimmick gone wrong — gimmick based on faulty assumptions regarding what movie-goers want and how they decide.

To really capture the essence of the original board game, Guber decided to give the film three different endings. When you watch Clue at home, each of its endings play back to back. But when the film first premiered in 1985, different theaters were given different versions, each with only one of the three possible endings. The assumption was that people would go back to see the movie again in different theaters so they could experience the thrill of each ending, thereby driving record box office sales.

Here’s how it really happened: People waited to see the movie until their pre-Facebook social networks could recommend which version of the movie had the best ending. They didn’t actually want to go see the movie three times in order to see all three endings, which meant a whole lot of people who wanted to see Clue in theaters ended up waiting until it came out on VHS.

Peter Drucker once said: “The aim of marketing is to know and understand the customer so well, the product or service fits him and sells itself.” In order to develop a product or service that fits your customers well enough to sell itself, you’ll need to have an intimate understanding of who your customers are and what’s going to fit them.

Understanding what your customers want and how they decide considerably reduces the risks inherent in decision-making. At the end of the day, you have to make sense of your customer before you can make sense to your customer.

So how do you sleuth out what your customers want and how they decide?

Talk to your customers, one-on-one. People rarely relate a defining brand experience in a survey box with the same detail and verve that they would in a conversation. Relational, down-to-earth interviews that encourage storytelling will tell you far more about what your customers want, how they think and what’s influencing their buying decisions than will surveys and focus groups.

When Febreze first launched, it was completely odorless and unscented. The team behind this remarkable odor-eliminating wonder-spray believed that the ability to completely eliminate odors would relevantly differentiate this product in a way that would make it a revolutionary household staple. Instead the newly released product floundered and sales soon dwindled. Eventually Febreze’s marketing team started interviewing women (yes, terribly sexist — but that’s a different story) in person, one-on-one, as they cleaned their homes. Talking to customers about their cleaning rituals revealed that Febreze’s lack of scent left them wanting more. After they’d cleaned, they didn’t want their home to be odorless — they wanted it to smell fresh and clean. The smell of a clean home was the reward for their hard work. And so Febreze’s formula was tweaked, the marketing underwent a repositioning effort — and sales doubled within two months, reaching $230 million within a year. Now Febreze’s product line includes odor-eliminating laundry scents, car air fresheners and candles. Febreze would not be on the market, let alone under your kitchen cabinet right now, if their marketing team hadn’t taken the time to talk to customers one-on-one.

Get on the ground and in the trenches. If you need to know what influences whether or not hospital patients and visitors use parking valet services, work as a hospital parking valet. If you need to know what influences whether or not a brewery’s taproom visitors buy brewery swag, work behind the taproom bar. If you need to know where there’s a gap between your customers’ expectations and their actual experience, sign on for a few shifts in your customer service department. This is called experiential research, and it’s just as important as talking to your customers openly about what they want and need. If Henry Ford had asked his customers what they wanted, they would have asked him for a faster horse. Talking to customers will only get you so far — you have to understand your customer, your experience, your value and your market.

Tap your insiders’ expertise. Utilize cross-functional teams to tap the customer insights of your insiders: What do the operational experts already on your team know about your customers? Engaging your parking valets, taproom staff and customer service representatives in the decision process ensures that the people who know your customers best are actively contributing their insights and feedback, early and often. Top-down decision-making that fails to tap the insights of the team implementing your business plan and delivering on your brand’s promise to your customers, day in and day out, increases the likelihood of blind spots, mistakes and missed opportunities.

The real secret to understanding your customers is to make it a priority, and to keep your finger on the proverbial pulse. The more competitive your market and the more innovative your field, the faster your customers expectations will shift.