If all your customers are winners, that's bad.
If all your customers are losers, then you are making some money, hopefully that more than covers your overhead, but you're not maximizing your potential profit and eventually your customer base will get tired of always losing, even if you rebate them some of their loses.
Somewhere in the middle is the happy peak of maximum profit and it is the job of casino management to find that peak. At the peak, some of your customers will be winners, but you can't let that effect you emotionally, remember your job is to maximize the rake. Celebrate the winners, they bring in more business for you, and more business is more rake. You get the last laugh, because your profit will be orders of magnitude more than the winner's take.