I was going to say, how curious it is that Finns don't complain or give much feedback, but then I remembered I was just at a restaurant a few days ago where the food and service were both mediocre, and when the server guy asked us how it was we both lied and said "great".
In general though I would say Americans are very good at making their opinion known if the food/service aren't up to standard.
"Great" just let me get out of here.
I think that when a customer is actually satisfied, it is pretty obvious to anyone paying attention. The thing is, people aren't very good at reading others these days.
Maybe we should all just carry around little cards with various emojis on them to indicate our feelings. Great food? Drop the yummyface card. Bad service? Slap down the sadface card.
Where I grew up in Brazil they had steakhouses where all you had to do to indicate whether you wanted the food they brought out, was to flip a little card to the green or red side to indicate yes or no. Like this.