Passphrase interference

Recently I was giving examples of the kinds of passphrases that are easy to remember but hard to guess. There are some passphrases that I use frequently and have for quite some time. I do not write them down because I wish them to remain secret. I was alarmed to discover that, after giving these examples, I could no longer recall part of a passphrase that I use a lot. Fortunately, it came back to mind in the end. Henceforth, I shall take care not to think of alternative passphrases. So much for being easy to remember.