In third grade I had this teacher who would give every student the same grade on each assignment. After the A at the top of the paper, she’d mark all the wrong answers with a red pen, and then would come by each student’s desk to talk to us about where we went wrong. Together we would fix each sentence or math problem until it was right. 
At Parent night, one of the dad’s complained that his daughter worked hard to get her A, and that some of the other kids deserved to fail. The teacher allowed him to finish talking, and then responded in the same polite tone she always used in the classroom. “I’m not teaching your children how to pass test… I’m guiding them on how to learn.”
Months later our teacher posted everyone’s final grade on the board, and at first, no one was surprised to see we all had A’s. But after looking closer at our papers, and book reports, and our final assignments, we didn’t see any red ink on them.
I don’t think we should lie to children and tell them they got it all right if they didn’t. That doesn’t help anyone. But I also know that if you keep telling a child they are a failure; they messed up; or they did a bad job, after a while they’ll start agreeing.