RetweetJaVu
Someone in your twitter timeline retweets a tweet that looks so familiar you can swear you already retweeted it but you have not retweeted it yet.
I could swear I already retweeted this tweet from Instapundit about Jerry Springer saying he is the Father of the Destruction of Western Civilization. I must be suffering from RetweetJaVu! Oh well, not too much hassle to retweet it now.