These tips are from Gretchen Rubin's Happiness Project website, and if you follow them, you will not only help the speaker, but will avoid annoying the rest of the audience. How's that for incentive?
Here are a couple of good Q&A habits mentioned in her list of ten:
Pause for silence – don’t talk over a chattering crowd.
Don’t be long-winded. And...
Plan it out. This will help you avoid being long-winded.
And my favorite:
Don’t ask double questions. Give other people a chance.
It is indeed the speaker's job to manage Q&A, as I discussed in this post, but as an audience member, you also have a role to play.
How many times have you sat in the audience while someone else droned on and on with a question that was only relevant to himself? Or told a long story? Or hogged all the time with question after question, not giving anyone else a chance to talk?
Do you want to be that person? I didn't think so. Be considerate, be thoughtful, be concise.
Now go read the rest of Gretchen's list. Great tips!