Why do customer service people rarely do what they say they will do these days?

Unfortunately over the years the art of customer service has declined. the customer is always right was a phrase that was widely over use and has been exhausted and the customer also has taken advantage of that. I worked in a restaurant for a strong number of years and watched many guests complain and gripe to get free items. I take great pride in giving exceptional customer service and it deeply hurts when it goes unnoticed or unappreciated I can swallow no tip but I I am deeply saddened by zero appreciation and I end up taking that home with me.