Avoid them if possible and escape ASAP if you can't.

mrsconn23

Dear Prudence,

I work in construction. A few years ago when I was a recent hire, a person in a senior position tried to get me fired. They complained to the project manager about me, left all their work to me, and then publicly humiliated me when I made a mistake. They would also disappear for hours in the middle of the workday and hide my possessions under the guise of “tidying up.” The project manager got rid of them after a few months. Four years later, I’m still with the same company and this person now frequently visits my office as they are working nearby with a different company. How do I keep my cool around them? I don’t think they know I know they tried to get me fired, but I don’t want them thinking they can get away with being chummy. I also don’t want to stoop to their level!

—Not Fired, Just Fired Up

charlotte989875

Avoid them if you can, if you can’t I’d adopt the professional but not chummy attitude towards them especially if you have to interact with them in your job. Don’t stoop to their level, don’t tell people what they did, but also don’t act like you’re besties. They did a bad thing and you don’t have to act like that’s fine. 

banana468

Be a professional and not a friend.   You don't have to act like a friend to people who attempted to get you fired. 

MissKittyDanger

Act like a professional. If you don't have to be around them, don't.

VarunaTT

I don't have enough info, b/c I find it weird that this person that a manager "got rid of" is now visiting the office?  For what purpose?

I'd have no issue telling someone that was let go, to not darken my office's doorstep and be professional about it.  If it's truly an unavoidable situation (former worker is dating boss or something?), I'd just try and avoid them as much as possible and plaster a smile on when it wasn't, to escape ASAP.