A floater pharmacist was assisting a customer at the pick-up counter while the pharmacy's experienced technician was on a break. The pharmacist inquired about the patient's name and date of birth and retrieved the patient's prescribed medication from the waiting area, informing them, "We have your blood pressure medication today." The patient acknowledged this. However, when the pharmacist attempted to scan the barcoded label against the pick-up screen, an error message kept appearing. Believing that the medication had been reissued due to the hectic nature of the day, the pharmacist printed a new label and affixed it to the medication vial. This time, the system scan was successful, and the patient paid for the medication before departing. Several days later, it came to light that the pharmacy had mistakenly provided the wrong medication to the patient. The mix-up occurred because there were 2 patients with very similar names, John Smith and Jon Smith, both of whom were receiving hypertension medications—one lisinopril 40 mg and the other spironolactone 25 mg. The pharmacist unintentionally chose the wrong patient's medication from the pick-up area and then printed a new label. What elements contributed to this error?