I made a mistake when I wrote the listing for my little birds...
Got too specific with it, when the listing was meant for a collective.  So instead of writing it as "you get one of these little birds", I wrote, "you get this bird, or convo me for a different one".  Bad form, really, borne of ignorance. 
I sold a lot of these birds-on-blocks at the King William Fair last April,  which is good, but I forgot to update the listing, which is bad.  So a lady buys the L bird and the bird on the collective listing, only I don't have it anymore.  I'm hoping she will be happy with one of the others...
Revised the listing this morning, and loving the new photos, but I really hate when I make a dumb, avoidable mistake and cause someone an inconvenience. 
 Now to remind myself Pobody's Nerfect and get on with my day.