How do you talk to people enough to be polite, without getting them started on a talkathon?

I hate pointless chitchat, but I do it, because people will think I’m rude if I don’t. It’s a social norm.

So this morning, two coworkers and I were talking about what we did this weekend. Bob just veged out - not much to tell about that. I went to a movie, and briefly described it.

Then we get to C. C went to an extended family event, and had to give a detailed description of every person there, their characteristics, why C thinks they’re that way, psychoanalysis, etc.

C, you’re verbally writing a book. All you need to say is a paragraph.