@LaffingBear is right, it is how well they did respective to your expectations.
Given a local restaurant charges much less than a Michelin rated one, you can give them 5 stars if they met all your expectations, given the price you paid.
Similarly, a 5 star hotel at $500 a night that had a rude guy at the front desk deserves a bad review, even if everything else was perfect. At that price, they should have enough money to train him appropriately.