Sometimes bad feedback is a good thing
We all want each and every project we do to be perfect but that isn't real life.
So your great job you were going to be profitable on no has an angry customer and one that can make everyone miserable for the remainder of the job if not addressed right away or one that has everyone walking on eggshells and rushing to get done, or worse yet you have the customer who says nothing, you have no idea they are upset and they hir you with a bad review with your painters and office thinking everything was great.
This happens all the time and it knocks the wind out of everyone each time, trust me the painters and staff want nothing more than to make people happy from the customer to their supervisors to themselves, if you're in the painting industry you are a people pleaser for the most part and any bad feedback cab send us into a dark hole.
But don;t crawl in that hole, sometimes yes it may be a customer that no matter what you do nothing will make them happy, for people like this, smile and get the job done and move on, learn how to pre-qualify your leads better and learn a lesson but for the issues that are real where you missed satisfaction step back and thank the customer for bringing these issues up and use it to train yourself, your crew and staff in the office.