Yeah, that’s exactly my point, not a thing in Greece 😄

In North American Greek restaurants they have this little show/ceremony thing where they during serving a plate of saghanaki they light it on fire (flambé-style) and shout “Opa!”. It’s meant to look like a traditional Greek thing (no doubt influenced by movies like Zorba the Greek, that movie is responsible for so many cultural inaccuracies).

in addition to what the other post said which is all correct, “opa” is like “oops” in greek, people will say it when they trip over or spill something.