Today I went to sign some copies of Love and Other Wars at Goldsboro Books, a gorgeous little bookshop on a backstreet in central London that inspired Diagon Alley in the Harry Potter books. They're super supportive of unknown writers (like me!). So when an obscure military guy by the name of Robert Galbraith published a crime novel a while ago, they ordered lots of copies, unlike other bookshops that ignored him and banked on well-known crime writers instead.
Galbraith was very reserved, not surprising given his military background, and they had to send the copies to him to be signed.
And then... the news broke that Galbraith was JK Rowling. The publisher re-printed thousands of copies mentioning the JK connection. Which meant Goldboro was suddenly the owner of dozens of extremely rare first editions signed "Galbraith" (later copies were signed JK & Galbraith).
When I prodded them today for more gossip, they eventually revealed that they'd received a personal thank-you note from JK for championing her book when few others were interested. You might think they'd frame it and put it in their window, but that's not their style.
The fact that a Harry Potter tour group was standing outside the shop as we chatted, marvelling at the model for Diagon Alley, somehow made the whole story all the more magical.