My employees have always been happy. They are either happy and self confident or insecure. Most people don't know how to run a business. That's why so many fail. The boss wants to be liked. They want friends. It's a popularity contest. They keep poorly performing workers because they are nice or really need the job. A burger flipper who looks forward to 20 years on the job as a burger flipper should have another job. One more inspiring.
I took a shabby kennel built to hold about 90 dogs and 5 years later we'd built onto the property so much we can hold over 200 and now have a boutique and grooming salon. Now, it's not all to my credit. The owner was willing to invest in her business, and between the two of us we found great employees who helped build this into what it is.
I don't care if my workers like me, but I find that when they like their job and actually want to come to work, they do a better job. And a large part of that is making sure they are paid accordingly.