I had an instructor who was a prosecutor. He called a witness who had seen the whole thing, and had an interest in seeing the defendent punished. Slam dunk case.
She thought she was on TV. She overacted EVERY WORD. Completely embellished the retelling of the events. Didn't lie, but she was the center of her version of events.
He said you could see the faces of the jury members sour minute on minute. He lost the case.