HCI work on affective interfaces has focused mostly on emotional awareness, reflection, and regulation and less so on emotional appraisal which supports understanding the causes of emotional events. While emotional appraisal research has involved methods of eliciting emotions from photos, imagining scenarios/vignettes, or recalling past emotional experiences, we propose the Emotional Appraisal Kit, a novel method to explore appraisal in the wild. We present a one-week diary study with 18 participants to explore this kit and its bespoke probes whose design has been informed by Lazarus' appraisal theory. Our findings highlight the value of implementing emotional appraisal interfaces not only to support self-reflection but also, to enhance emotional awareness, understanding, appraisal and regulation.