Out-of-classroom communication (OCC) in the form of email has increased considerably in the past few years. This study uses Interaction Adaptation Theory (IAT) to inform and frame the impact of using overly casual email messages with instructors. Study one used an experimental method to determine that message quality (casual vs. formal messages) accounted for between 48% and 64% of the variance explained in affect toward the student, student credibility, and message attitude. Message quality also significantly impacted on an instructor's willingness to comply with a simple request for a face-to-face meeting. Study two further examined these findings using a comparative analysis of both instructors and students. Findings reveal that instructors are bothered more than students by overly casual email messages. Instructors attribute students' use of overly casual emails more heavily to training issues, while students attribute this to technology use. Two specific email violations that bother instructors more than students are emails not signed by the message sender and messages that include shortcuts like ''RU'' instead of ''are you''. Finally, it appears that instructor generational differences have little impact on these descriptive findings.Recent instructional literature is replete with evidence that the studentÁinstructor relationship is valuable and creates many positive outcomes for the student (Frymier