On the surface, the concept of clinical checklists is enticing in its simplicity. If a clinician would just take the correct steps, at the correct time, following a set protocol, we could achieve zero preventable patient harm, right? Unfortunately, real-world complexities interfere with this ideal. Every patient, surgical procedure, and clinical scenario is different. In this manuscript, we will first review the history of checklists in modern medicine and then dissect the reasons why clinical checklists are sometimes ineffective. Next, we will examine some specific situations where checklists can be useful, including regional anesthesia and critical events.But why would we want a checklist anyway? Despite these disadvantages, a well-thought-out, comprehensively tested, and regularly revised checklist can serve to aid the