Back in 2015, my spouse sent me 0.1 btc for my birthday, which was worth $30 back then. But he sent it from his bitcoin wallet, which he'd painstakingly downloaded (took three days to download the blockchain and sync the wallet) - he did it that way because the wallet allowed him to include a message, and he typed in a short poem to me that he had written.

Anyway, that poem is now forever in the blockchain, and that is my most treasured bitcoin memory.