DEAR MISS MANNERS: We threw a small potluck birthday lunch in the break room for one of our co-workers. About four of us contributed; we all work directly with her and know her the best. We put the leftovers in the fridge, and later in the day, a co-worker who hadn’t been at the party helped himself to them.

Co-worker eats leftovers that aren’t his because he says, “once something is shared in a public place, it becomes public property.”