You may find, Guest, guest - that your performer was sick. I have had that happen to me, at the end of a perfomance - where I was expected to visit for a while and be available for conversation, and I was feeling terrible. I was not rude, and I tried to be engaging, but while I'd had enough energy to get through the show pretty well, once it was over I was ready to drop. I'm sure I looked unfriendly, like I couldn;t wait to get out of there ... that's because that's how I felt at that moment. Some people may have been thinking "what an a*shole"

When it comes to your performer in this scenario, you might want to give him the benefit of the doubt, and judge a tree by its fruits - if you've enjoyed his work before, and felt an affinity with him, trust that there may have been good reason for his sour demeanor that day, and it was just a passing thing.