My nan sent me a card for my birthday the other day; then, last night she sent me a text asking me if I enjoyed my birthday celebrations. I sent her a text this morning saying that I had, indeed, enjoyed my celebrations, and thanked her for my card. A few minutes later she texted me back to thank me for my text.
I briefly considered sending her a message to thank her for thanking me for my message thanking her... Then I thought the universe might implode, so I didn't.