The restaurant in a hotel was short-staffed. For about 10 tables, they had one cook and one server. Service expectation is a stretch but possible with experiences and skills.
It took a while for the server to come around and get our order. Since we were on vacation, we had time and patience. When the server brought food, we noticed a dish was missing. It was left out from the order. The room was full and the cook was overwhelmed. When the server learned about the missing dish, he was reluctant to come back. Eventually we waved him down to pay the bill and left feeling short.
We were not upset about the mistake, but how we felt afterwards.
Good service is never about mistake free even though making less mistake is preferable. Good service is about what to do when mistakes happen. Order skill is one thing, but empathy and care is another.
Apologizing for mistakes and understanding how disappointed customers feel are good enough to let people know that they are seen and understood. With the given situation and reality, he might be surprised to know how much his customers are willing to cooperate and reciprocate.