I work a local science fiction/fantasy convention here in Atlanta. A couple of years ago, the person that I work for was driven crazy by a couple of people that worked for us. He plainly told me that he did not want them working for us again.
So after the convention ended and we were into January of the following year, he posted on our yahoo group asking who was planning on being on staff with us for the year. I forgot that when one replied on the group, it went out to all members of the group. I posted about the couple in question and stated that he did not want them working and did he not remember stating that. As soon as I hit the send button, I got an email. From me. Of the post that I had just put out. I immediately felt sick, and hot, and awful. I tried to retrieve it, but was not able to. It went out to the entire group, including the couple who I had been told he did not want working.
I had to totally backpedal and immediately email the woman and tell her I meant someone else and not them. It was awful, she probably knew I was lying, but played along.