Waiter: “How was your meal”
Me: “Mmmm, delicious, very good, thankyou”
While this can be the case it is sometimes not. However to avoid embarrassment on all levels effusive gratitude is the norm. I have even tried giving honest and reasoned assessments such as the “the vegetables were not al dente, but the sauce was the right consistency and not over-seasoned….” etc. etc. You see the problem, its just easier to lie.