"Find fault" is a commonly used expression that generally means to criticize or point out flaws in something or someone. However, there are several alternatives to this phrase that can convey the same meaning in a more subtle manner. For instance, one could use "identifying shortcomings," "spotting imperfections," or "detecting flaws," to convey the same messaging. Other synonyms for the expression could be "singling out errors," "naming deficiencies," or even "specifying shortcomings." All these alternatives can help one to express their criticism in a way that is less harsh or judgmental while still achieving the desired objective.