How to deal with a supervisor who constantly points out my mistakes?

I work with a woman who constantly highlights any errors I make, even if they are minuscule. She is very good at her job and rarely makes mistakes, though feels the need to ram mine down my throat. She has been a "friend" of mine for about 20 years, though I feel the friendship has run its course. Why do people feel the need to point out others errors, even if they don't make many of their own? It's like she has zero tolerance for errors, and if someone else makes a mistake I hear how she talks about them behind their backs. I am pretty sure she talks about me that way too. Time to say bye bye??