That's what i have thought all along, Nicola, you can get eight 5 star reviews in a row and your score doesn't budge. but one novice client can't explain what he wants and gives you a bad score to save face and your jss drops 3 points. I've been doing my job for 20 years and some kid rejects the job because I made it blue and he forgot to tell me he wanted red and that reflects on me??? ! it would take 2 seconds to change the color but he's already asked for a refund and is nowhere to be found. it's utterly preposterous.
And there is zero oversight so clients can do whatever they please and the only way we can stop them is by paying $300 for an arbitration which you lose even if you win. And i did a near freebee job for one client because he promised to put me in a talent cloud and said i'd get a lot of work from him. Why did i believe him? Because Upwork recommended him and referred him to me. I rushed the job, overdelivered, he loved it, never saw him again. we are literally chopped liver haha!
I literally take any promises made to me by clients with a pinch of salt. If they come through and deliver I am pleasantly surprised. If not...hey, didn't expect them to in the first place.
This gets back to what Nichola and Irene mentioned - there are always those clients who will never give 5/5 to anyone no matter what. I remember teachers like that in school. Got 95-100% on all my work, but one in particular would never round up.