People Take on the Traits They Describe in Others
Spontaneous trait transference is a phenomenon where people are perceived as possessing a trait that they describe in others. Telling others that your math professor is lazy will cause them to infer that you are lazy. This works the other way too — describing positive attributes about your friend may ascribe you those attributes as well.
Several experiments showed that people will associate personality traits to communicators mindlessly without logical rational. They also have a poor recollection of whether the communicator was describing themselves or someone else in a conversation.
So be careful when gossiping about a co-worker, lest you be seen as what you describe. And if you want to appear more charming, perhaps you could add that word to your vocabulary when talking about others.
As the old saying goes, “If you can’t say anything nice, don’t say anything at all”.
Skowronski, J. J., Carlston, D. E., Mae, L., & Crawford, M. T. (1998). Spontaneous Trait Transference: Communicators Take on the Qualities They Describe in Others. Journal of Personality and Social Psychology, 74(4), 837-848. [PDF]