Yes, a person who worked for me for several years. I had (I thought) always treated this person fairly and believed they were trustworthy and actually liked me as a person. They were always there at the business to lend an extra hand or be helpful in some way and I returned the favors. I appreciated everything and gave them a few things of mine (including a full frame camera, bag, lenses, etc) which I had no more use for.

As time went on, I found from other employees the bullshit stirring they were doing behind my back. The bottom line was they were unhappy with how compensation was being split among fellow employees. Instead of coming directly to me, which I have always encouraged, they thought it best to talk behind my back and attempt to get other employees to follow their agenda. (I think that part hurt the most) Then they posted a thread on Reddit hammering my character and filling it with half-truths and inneuendos.

After that I kept my mouth shut and decided they would be treated the same as everyone else. No special favors, nothing extra. This was to go on for the rest of the time they worked for me.

They gave their notice they were leaving and on the last day I thanked them for their time here while addressing them by their username here on Reddit. People, I wish I could describe facial expression when I dropped that piece of knowledge on them. It was a thing of beauty to me. Finally, I let them know that I would provide a reference that would be equivalent to their posts about me online. Needless to say I was never contacted by any future employer of theirs.