If you work in any small business, it may have been the UPS driver. I know, you're thinking that UPS makes you sign for deliveries. Not always, and especially if I was your delivery driver.
The most irritating aspect of a UPS driver's day is wasted time spent waiting for a customer. Trying to get them to sign for packages or having to wait for that package the customer desperately wants to ship that day but procrastinates until the driver shows up. Then they suddenly spring to action.

Finally, package prepped and in hand, she leaves for the guard tower out front, which will take at least three minutes to maneuver among three electric gates that she has to be buzzed through. The dreaded time sink she's created for the UPS driver is now between 10-15 minutes.
I told the nurse in a serious, but tactful tone, that her nonchalant method of making the UPS driver wait for her package creates substantial time troubles for that driver the rest of his day. A UPS driver's job performance is judged solely on stops per hour. You can be the best customer service rep UPS could ever hope for, but if your stops per hour are off more than 2 per hour standard that UPS adheres to, then management will be riding your ass, tagging along thinking you're fluffing off while on your route.
That's the very last thing you want.