When you get a bad review, don't respond right away. Sleep on it first, then write something measured and professional. How you handle criticism shows your character and shapes what customers think of your business.
We have customers that are absolutely adamant they can't have any bad reviews. How do we get rid of this? And actually, you really demonstrate what you're about as a business and/or a person in how you respond to difficult feedback. So what impression are they going to have of you when they read that? If you're a small business and you're a one-man band or anything like that and you're feeling angry about it, take a night. Yeah, sleep on it or write something and sleep on it, but don't send it straight away. See how it reads the next day. And you kind of go, actually, there's nothing in that.