During peer review, students often exhibit resistance when asked to respond critically to their peers' writing. Most students tend to offer gentle critiques, especially when they personally know the peers whose writing they are reading. This tendency to be overly kind can be frustrating for instructors, yet there may be logical reasons for students' hesitancy to engage in critical peer review. This study explores students' peer review letters through the lens of linguistic politeness theory and illuminates one possible explanation for the reluctant peer review.