What Is Dangerous About A Fee-For-Service System?

If I get paid for seeing you in the office or running a task, if I get paid for only operating and you not stop not for swearing operation, I am going to do more of that stuff and even when it might be marginally beneficial and we have plenty of evidence that we are doing unnecessary tests and treatments all the time and of course we can come up with rationalizations why in this case it's really important, but has taken across the system it's both wasteful, unnecessary care and therefore harms people.