Returning an item is a heavy burden on 'Task Sequencing'—the executive function responsible for breaking a large goal into smaller chronological steps. In ADHD, task sequencing is severely impaired. The brain cannot "chunk" the steps smoothly. Instead of seeing 'print label -> tape box -> drive', it sees a massive, overwhelming singular block of friction.
Secondly, the neurobiology of motivation requires a dopamine delta (a difference between expectation and reality). When you buy an item, the anticipated reward releases dopamine, prompting action. When you return an item, the action is preventative (avoiding losing money). Preventative actions offer almost zero dopaminergic reward. Without dopamine acting as the "activation energy," the task initiation engine simply stalls out.
Finally, 'working memory' failures sabotage the physical process. You remember to print the label at 10 PM. You cannot go to the post office at 10 PM. You leave the label on the printer. The next day, you drive to the store but realize you left the label at home. The sheer frustration of the failed sequence triggers task avoidance, guaranteeing you will never attempt it again.
