This didn't annoy me, but it was shocking/gross:
We had the annual meeting today where they said how the company did last year. It's always followed by a catered lunch. The guy next to me had to catch a flight and left his dessert half eaten. A few minutes later I watched as another guy at the table start eating it. WTF.
For context these 2 aren't related, romantically involved, or even close friends. I'm not sure the guy that left for the airport would have been ok with guy #2 eating off his plate.