@Andrea-and-Ursula0, there is a way to see who noted you how: on your computer account, go to statistics, scroll down and open the details. Note the stars as they are and next time you can see the difference and note the individual ratings of the last guest. (Sometimes single ratings disappear but it's quite rare)
There is no way to know why someone gave 1 star or 5. - I proposed once that for less then 4 stars a guest should be prompted to give a reason, but it was one of those ideas called a good idea that never manifest itself as a function.
Sometimes guests leave a reason in the private feedback.
If you keep a list, you will notice over time which kind of guests will give you 4 stars or even 3 no matter what.
It's just a crazy system, presented to everyone without explanations and the same scale of values fits everyone all around the world.
France is seriously discussing to oblige all internet platforms who use a rating system to explain it to the users and to explain the consequences of the rates they give. I hope it makes it into law. ;-))
