I have a certain co-worker in my area who very frequently questions the way I perform my job. This co-worker is not nor has ever been a supervisor but talks to me as if they were management. I do my job as I was trained to do and I have 10 years service at UPS so I definitely know what I am doing. This person has been at UPS half as long as I have and has no where near the experience performing the job as I do. This co-worker also criticizes and says that I don't work with the team. (there are 5 people in my work area including myself). I work with them as a team as much as I can but never have officially joined the "clique". I basically come in to UPS ,do my work as I am expected to and go home. Tonight this person got into my face yet again and I told said person "You are not my supervisor, quit questioning me and telling me what to do. Shut up and get out of my face". Said co-worker then said " Don't tell me to shut up again or I will report you (for what I do not know-telling them to shut up????-thin skinned aren't we) I just looked at this person and said whatever and returned back to my work thinking it was over. This co-worker then says "oh, you don't think I will?" I just ignored the comment, saying nothing further and finishing my job. Now a few questions here. 1. How would you handle an obnoxious overbearing co-worker like this? 2. Could this be considered as harassment and 3. I felt like I was threatened by this co-worker due to the fact that they said they "would report" me even though I have done nothing wrong. (I construed this as a threat because she would be going to management and telling lies about me therby causing management to question me. I know this co-worker is just trying to intimidate me but I don't need management on my case if I've done nothing wrong). Basically looking for answers on how to handle the situation. I just want to do my job and not be "harrassed" by fellow co-workers.