Informed by a learner-centered and socio-constructive approach to the impact of feedback and drawing upon critical incidents from 1,075 Chinese EFL university students and semi-structured interviews with 29 of them, the present study aims to reveal the negative side of feedback by examining its negative influences on L2 student writers and their responses to such influences. Findings reveal seven feedback attributes that could elicit negative impacts on writers: lack of specification, low quality, superficial feedback, unclear feedback criteria, inconsistent feedback, one-way communication, and unclosed loop. Feedback of these attributes could negatively impact students’ writing practices, learning emotions and motivation, and social relationships. This study has also found that in response to such negative influences, students would pay selective attention to feedback, accept/reject all the feedback, or seek external help. Based on the findings, a multi-dimensional model concerning the negative side of feedback is proposed, and how writing teachers could alleviate the negative impact of feedback is discussed.