What words should be written in restaurant ornaments and calligraphy?

Drink well and eat well.

Explanation: After eating (drinking), I feel comfortable, enjoy, be happy and enjoy the virtues of my ancestors. Simply put, drink harmoniously and eat ethically.

Source: "Zhuangzi Zeyang" comes from "Drinking Harmony": "So don't say it, you can drink people to make peace"; "Eating morality" comes from Zhouyi Litigation: "Sixty-three, eating old morality".