Recent research has focused on mind wandering (MW), which is caused when a person’s attention shifts from a primary task to unrelated internal thoughts. One of the research interests for this psychological action is the diversity of MW content: from the future to the past, from the real to imaginary worlds, and from internal and external distractions. However, to date, there have been only a few studies that have explicitly examined MW content. Therefore, we attempted to fill this research gap, to some degree, through this exploratory study. We used an unbiased method that allowed the 59 participants to freely report their psychological experiences, after which their answers were categorized post hoc, to avoid any acquiescence. We found a substantial number of task-related thoughts, or task-related psychological experiences, during the typical MW task. The experiences were further analyzed using a data-driven method, which reported that metacognitive ability possibly contributed to MW. The occurrence of task-related thoughts and metacognitive ability should be given attention when evaluating MW.