I have a tendency to be too concise for most people when speaking. I don't expound on things very much, and the thing that makes me nervous is that I'm usually expected to expound or even embellish and pad things that would otherwise be simple.
I never know what to say when people expect to be entertained out of nowhere somehow. When I know what I want to say I can say it, and I can deliver information that I find relevant. It's hard to not be prosaic when talking about something that I don't necessarily want to talk about.