As I'm sure others probably do on here, I've dabbled in bits of acting in the past. Some for money, others for fun. I know if I had to go into a hall in front of a large crowd to answer questions relating to something I did years ago, I would probably dread it a little. Some actors love or are happy to embrace the convention atmosphere, others are simply there for a bit of extra cash. I understand both positions.
I read somewhere that in the early to mid-1970s, when Shatner was far from rich and pretty much had to accept convention gigs, he went on stage with dramatic readings and planned stories.
The fans loved him, but what they really wanted was Q&A. And con organizers had to coax him into adding that section to his act, because he considered the unplanned stuff to be the most daunting. You never know what someone might ask, and you're on the spot for understanding nervously worded questions, having quick recall for meaningless past events, and while you're at it, trying to be witty and charming.