If you don't know him, don't judge too quickly. He may be a complete unprofessional jerk, or he could have the Peace of Christ, Contentment of Buddha, or something similar in him. I had a similar recent experience.
I was my company's sole onsite representative for a very contentious machine problem that was costing the customer lots of money per day. Over the course of three weeks' investigation using Six Sigma methods, I proved the major cause was due to the customer's own people & processes. They fought this notion tooth and nail, but I ultimately proved it through patient experimentation and data analysis and took them from 35% scrap to 0%. But every day we had to have a conference call across two continents and three companies with High Level Managers attending. The very first day I was in the Plant Manager's office with him, the Tech Services Mgr, and the Mfg Engr for the process. During the course of the conference call, the Plant Mgr was screaming at the phone, and all three of the customers were smirking, rolling their eyes, chuckling under their breath, etc., in response to discussions from my company's engineers, managers, and salesmen. Very inappropriate, unprofessional, and disrepectful behavior that had no place in this very serious situation. When I was asked for my opinion on a particular point, I started my response by saying, for all to hear, "Well, I am having to endure a lot of smirking, eye rolling, and other unprofessional behavior in this room, but I think blah blah blah."
Gutsy, maybe foolish, move on my part in retrospect. But it shut those clowns up and exposed the situation I had to endure every day. I joined the remaining conference calls from my car in the parking lot every day after that. After it was all settled and done, I got praise from the Parent Company's Director of Purchasing and a "pat on the back" bonus from my president. Now that same Jerk Plant Mgr likes it when I show up at his site.
Two morals: (1) don't judge too quickly, that is the job of Someone Else. (2) Stay professional always. You will be remembered for a few years for grace under pressure, but no one will know or care in a hundred years.
Besides, it's just work.
TygerDawg