After the incident, she admitted that she had a chip on her shoulder.

chip 本义是"碎片、薄片"，在这个习语中比喻"心中的怨气或不满"。 shoulder 意思是"肩膀"。 have a chip on one's shoulder 是固定习语，字面意思是"肩膀上顶着一块碎片"，实际用来形容一个人因为过去某件事而一直心怀怨恨、容易发怒或对他人抱有敌意的心理状态。