pick (someone or something) to pieces
To make an effort to find flaws or negative aspects in something through excessive analysis or criticism. Every time I show my brother one of my stories, he just picks it to pieces without saying anything that he liked about it. Critics picked him to pieces for his performance, but fans of the franchise seemed to love it.
pick (or pull or tear) someone or something to pieces
criticize someone or something in a severe or detailed way.