I was just thinking of some of my most awkward moments.
One that comes to mind took place at the second law firm that I worked at in DC. I had been there about a month and I was starting to get to know the staff by name. So in an effort to be friendly (and also not forget names too quickly) I said hello to the fellow delivering the mail.
Me: Hey Robert, How's it going? (in a very cheery voice).
Dwight: I'm Dwight! Robert died two weeks ago. (In a very scolding and disgusted way).
Me: Oh. (long awkward pause - I mean really how do you recover from that) Bye (in a much less, cheery and wishing I was invisible voice).