There is a story that Chinese restaurants in early San Francisco would take their leftover ingredients at the end of the night and mixed them together into a entree they would sell for cheap. They called it Chop Suey. It ultimately became the most popular item on the menu.
Years ago, I was working near Milford, Utah. One evening I came in late and the only place open was the Chinese restaurant by the train station. The menu had various types of chow mein, including shrimp, chicken, pork, and beef. I ordered shrimp, and what I got had shrimp in it, also chicken, pork, and beef. They had apparently scraped out the remainders of all of them to make a serving. It was really good, though.