Let’s do lunch. Let’s get coffee sometime. By 1985 a Los Angeles Times columnist was already joking about the first: “Let’s do lunch sometime, have your girl call my girl.”
MIT’s office for international students explains such invitations to new arrivals. An American writer on the page says that when people say “Let’s get lunch!” it “seems like they don’t really mean it.” If an American is serious, “they will propose a time and place.”