Sales representative and after sales. If anyone of these factors fails to satisfy the need of the consumers, everything done by the company is lost. Technology, safety, investments and many other things became senseless to consumers. Because, the after sales could not provide the appropriate level of quality to consumers and the problem is not solved; the representative did not behave properly and consumers became angry! These two factors directly influence the emotional aspect of the consumption and change the perception forever. Not only perception, but also increase negative word of mouth!
People love to spread bad news to other people, when the topic is about a brand. If they have a bad experience with the brand, they would love to spread it to other people. And other people will love to spread to others.
In the end, lots of investment, technological advantages, differentiating characters are gone away. They might sound good but consumer will always remember that adverse behaviour.