I have never heard of anyone who has had a bad customer experience with Amazon, Apple, Costco, or Salesforce. The aforementioned companies are incredibly successful due, in large part, to a material focus on the customer experience. Not surprisingly, the stock market has handsomely rewarded these four companies over the past decade.

Amazon is so customer focused that it will literally send you a replacement for a lost package immediately without ever implying that the customer is at fault. The result is a consumer experience that is so optimal that Amazon is the only place where many consumers decide to shop online.

The same can be said for Apple when it comes to the in-store experience. Apple employees are so passionate about the products that I feel like I am talking to a polite tech enthusiast in the Apple stores and not Apple employees. The result is incredibly brand-loyal customers.

When was the last time we heard of a consumer switching from using primarily Apple products to non-Apple products? Apple’s in store Genius Bar customer-support concept is brilliant, and I can’t understand why more companies don’t do it. The result is Apple’s having the highest sales per square foot of any retailer in the U.S., at more than $5,000 per square foot per year.

The customer experience at Costco is also superb. In fact, Costco has the best return policy in the retail industry. We only buy televisions from Costco, given the company’s multiyear return policy. Costco also doesn’t even bother asking for a receipt when you return items (given the company’s digital receipt policy).

In addition, Costco has never raised prices on its fast food products; you still pay only $1.50 for the hot dog and drink combo, which was the same price Costco charged consumers 30 years ago! Most consumers don’t know that you can even trade in your old consumer electronic devices at Costco and receive a “Costco Cash Card” in return. A friend of mine jokes that “if you can’t find it at Costco, then you don’t need it!”

Not surprisingly, Salesforce, whose roots are in the customer relationship market, also has superb customer service. In fact, Salesforce is so customer focused and so transparent that the company will publicly disclose in real time when its cloud services are unavailable or having reliance issues. Consumer trust is of paramount importance to the company as “transparency builds trust.”

What we can learn from these four companies is that the customer is always right. In addition, it pays to be long-term greedy and understand that the optimal and highest lifetime value of a customer is a result of superb customer service.

Online ratings have altered the customer service role to the benefit of the consumer. Remember the days when taxi drivers were not that customer focused? Given the fact that you rate your driver on Uber, taxi drivers are now materially more customer service focused.

The same can be said for other industries where online ratings are tracked, including retail or auction companies like eBay, hotel services like Airbnb, teaching services like Udemy, and of course the restaurant industry through sites like Yelp. A few negative reviews can destroy a brand.

In conclusion, a superb customer experience begets more loyal customers who will no doubt spend more money on a company’s products or services in the long run. A superb customer experience also leads to higher stock prices over time. In this digital, social media age, if a customer has a poor experience, all of his or her online contacts might find out about it very quickly.

It can take 30-plus years to build a brand and just a handful of poor customer experiences to destroy it; a company is only as good as its customer service, and the customer is always right.