The phrase "pick flaws" can be substituted with several other phrases that convey the same meaning. For instance, one could use "point out errors," "identify faults," "spot mistakes," "find imperfections," "discern deficiencies" or "detect blemishes." All these synonyms suggest the act of finding and highlighting mistakes, shortcomings, or weaknesses in something. It could be a text, an argument, a performance, a product, or any other thing that could be reviewed and scrutinized. When this is done constructively, it can be helpful to the person or thing being reviewed, as it enables them to identify areas of improvement.