I’ve been writing about online reviews for ten years. You would think, by now, I’d have a pretty good level of smarts when it came to using that knowledge in practice as a consumer. For the most part, I do. The toaster I bought a month ago, for example, was the result of an hour spent reading reviews about toasters across a variety of platforms. I’m always amazed by how often I’m saved from a potential hassle, a disappointing product or a terrible buying decision by the words of strangers I will never meet.

Reviews are, quite simply, the perfect buyer’s guide. This weekend, however, I slipped up. I didn’t read the reviews first and narrowly avoided a potential calamity.

I’ve been helping my daughter look for a car, and it has been quite an adventure. The past month has involved far too many hours on Trade Me, trawling through listings, making choices and narrowing thousands of options down to a shortlist of suitable vehicles. I followed that with even more hours on Google researching each make and model and reading reviews from all over the world.

Those reviews were enormously useful. They helped steer me towards the makes and models I considered worth looking at, and by the weekend I was primed to visit a few dealers, inspect the cars and take them for a test drive. The cars I was looking at were all on dealers’ yards, and I’ve been on plenty of those over the years. I was fully prepared for the level of customer service I had come to expect from car dealers.

The first yard didn’t disappoint. The salesperson was attentive, informed, helpful and courteous. Unfortunately, none of the cars I drove set my world on fire, so I moved on to the next dealer. That’s where the trouble began.

I should mention something at this point. Although I had read screeds of reviews about the vehicles I was considering, somehow it never occurred to me to do the same thing with the dealers themselves. That was my mistake.

The next yard was one of many this company operates around the country. It would be fair to describe it as a budget dealership. The first dealership I had visited was of much the same ilk and had been perfectly good, so I wasn’t particularly concerned. I should have been.

From the outset, the level of service was woeful. In my 50-odd years on this planet, I don’t think I have ever met a car salesperson who appeared to have so little interest in actually selling a car. It was mystifying. The salesperson didn’t seem to know the vehicles on his own yard. He was rude, arrogant and generally unpleasant. At one point, when I asked him a question, he interrupted with: “Let me finish.” It sounded like something straight out of the Basil Fawlty school of how not to treat your customers.

Despite all that, I decided to give the car itself the benefit of the doubt. The test drive was good and, because I was interested in the vehicle, I put down a small deposit to secure it while I arranged an independent inspection. I figured the inspection would guide my next move.

The following day, I emailed the salesperson to let him know which inspection company I had chosen and what time they would arrive. Five minutes later, he called me. He told me they did not accept “private” inspection companies. I asked why. “That’s our policy,” he replied. I repeated the question. He then gave me an answer I still find extraordinary. “We find that they try to find fault with the vehicles.” I was shocked. “Well, that’s why I would want an inspection,” I replied. “And what you’re saying makes you sound incredibly dodgy.” He didn’t respond.

At that point, I told him I no longer wanted to buy the car from him and asked him to cancel the sale and refund my deposit. And then I did what I should have done before I ever set foot on the yard. I read the reviews.

The reviews for the dealership — and that particular location — were shocking. There were story after story about terrible customer service, with the salesperson I had encountered appearing as a regular character. There were allegations of devious practices, complaints about failures to adhere to consumer law, and a catalogue of unhappy customers. Then I dug a little deeper. A Google News search brought up reports of court action and stories about the company being fined hundreds of thousands of dollars following prosecutions by the Commerce Commission.

Suddenly, everything made a lot more sense. The signs had been there. I had simply failed to look for them.

What struck me afterwards was how completely inconsistent my behaviour had been. I had spent hours researching the cars. I had read reviews from around the world. I had compared models, weighed up reliability, considered other owners’ experiences and used the collective wisdom of thousands of strangers to help make a buying decision. Yet when it came to the people actually selling me the car, I did none of that.

I judged the product and ignored the business. That was a mistake I won’t make again. And perhaps that is the most important thing about online reviews. They aren’t just useful when you’re deciding whether a toaster is worth buying or whether a particular model of car is reliable. They can tell you something equally important about the people you are about to deal with.

In hindsight, it seems ridiculous that I researched a car so thoroughly but didn’t spend five minutes researching the dealership. After ten years of writing about the power and value of reviews, I should have known better. Thankfully, this time I got away with it.

Next time, I’ll read the reviews first.