I am referring to myself!
While I was on vacation, I sold two books on Amazon Marketplace - Northrop's Veiled Empire: Gender and Power in Stalinist Central Asia and Mahmood's Politics of Piety: The Islamic Revival and the Feminist Subject. Since I didn't take my books with me to Disney World, I had to email the purchasers and explain that while I couldn't send the books in the 2-business-days guarantee, I would send the items via priority mail instead of media mail. I heard back from one person, but I decided to send the other person his book anyway.
This morning after exercising, I was rearranging my bookcase to fill in the hole left by these transactions. With a sinking feeling, I realized that Politics of Piety is still here!
In my haste and sinus medicine-induced haze, I sent the second person - the non-responder - Badran's Feminists, Islam, and Nation: Gender and the Making of Modern Egypt.
So, I just sent another email to this guy explaining that I'm a dumbass and I'll send the right book tomorrow and would he please please please respond to my email.
I don't know which is worse....realizing your mistake and feeling shitty and embarrassed, or going along happily in ignorance until you're called out on it.