There is also unevenly distributed cultural knowledge: anything less than five stars starts causing hassle for the driver. I hate this inflation but I also wanna make sure the person who gave me competent service that I would realistically mark as three stars - not bad, not great, job done exactly as specified and I'm perfectly happy with that - is going to get five.
(hassle varies: offered fewer/worse-paying jobs is a good start)
When I moved to California for a while I once made the mistake of describing my food at a restaurant with "fine, thanks" when the server asked how it was.
Apparently this translates very differently in the culture of the Bay Area where it means something like "I am very upset" whereas in Boston I think this roughly would be read as "I am satisfied, but don't really feel like chatting."
There are clever words and/or phrases which do (or did) translate quite differently in British vs. American English. Starting with "clever" and "quite".
Key generally being that on a scale of 1--10, Brits tend to hover in the 5.00000003 to 5.000000031 range. Any deviation from that is an extreme reaction.
I've given up on leaving reviews. For 3 stars to be average, you need to actually give average reviews to some things, thus I rate almost everything as 3 stars which results in the "what went wrong", "Nothing, you were average, just like everyone else". I got sick of that exchange and gave up. Doing better than average is almost impossible in my book because almost everyone is doing their best. Sometimes someone will mess up and get a 1, but not often, and not bad enough that they make enough of a difference as to raise everyone else to 5.
Also, I just don't buy enough of most things to honestly know. Is Brand X thing better than Brand Y - how should I know? I don't have the time to spend a week trying each item to give a fair review. I happened to choose Brand X, and it is fine but it might really be far worse than Brand Y if only I had tried the other in stead.
(hassle varies: offered fewer/worse-paying jobs is a good start)