To keep a learner motivated, an intelligent tutoring system may need to adapt its feedback to the learner's characteristics. We are particularly interested in adaptation of performance feedback to the learner's personality. Following on from an earlier study that investigated the effect of generalized self-efficacy, this study examines how feedback may need to be adapted to the trait Conscientiousness from the Five Factor Model. We used a User-as-Wizard approach, with participants taking the role of the adaptive feedback generator. Participants were presented with a fictional student with a validated polarized level of Conscientiousness, along with a set of marks the student had achieved in a test. They provided feedback to the learner in the form of a short statement. We examined the level to which participants bent the truth as adaptation to the learner's conscientiousness. The study suggests that adaptation to conscientiousness may be needed: using a positive slant for highly conscientious students with failing grades.