I have a coworker who we'll call Roy. Rou and I work for the same boss, but we are technically in different departments. Because we work for the same boss, I often get assigned to work with him. The challenge is that Roy thinks he's above doing certain projects or tasks. He will outright say he isn't going to do something or tell our boss that he "better not start sh*t on Fridays" and that calling last minute meetings is "ridiculous". He is known for not helping or pushing work onto others when he feels a project isn't worth his time. Roy thinks very highly of himself, and to his credit, he has a long career of experience to back up his resume. We've both worked for our company for a little over a year now. My question is related specifically to an issue from today. Today we had a meeting with a potential vendor and asked him to give us a ballpark quote. While he was talking to the vendor, he started to badmouth our company. Should I discuss this with our boss, or leave it be? I don't want to go running to the boss and tattle like a school child, but I also don't appreciate the utter lack of respect for our company and the way he is presenting us.