I had a friend in teaching who claimed that she only found contentment when she took on adaptability as her mantra. As teachers we make a plan, but human institutions never completely conform, so that plan has to change. Once she accepted that, she could relax a bit when things didn't go the way she'd mapped them out.
I'm finding that trait worthwhile as a speaker as well. I have a dozen topics that I have outlined, practiced, and presented enough times that they're polished, but I've learned that adaptability is the best policy. For example: when I speak to writers' groups, I adapt the speech by questioning the organizers ahead of time: what sort of writers make up the group? What kinds of things do they write? Do any of them have publishing experience? Early on I found that poets don't relate much to the novel writer's journey. I also learned that I shouldn't assume the members of such groups actually want to publish. Many only want to write a rough draft and then dream that someone will find a page of their work on the sidewalk and scream, "I must present this to the world!" Too much talk of query letters and rewrites only confuses them.
I've also been asked to skew some of my talks to fit a theme. Most recently, a library participating in the 2010 Big Read asked if I could connect my mystery talk to Mark Twain. For a former English teacher, that is not a problem (think Puddinhead Wilson and Injun Joe).
I try as well to include Favorite Son/Daughter authors when I visit an area. Audiences like to get a nod to the local talent from a visitor. Adding just a few sentences makes me much more popular.
It's just good speaking technique to consider the audience and the the occasion. A little bit of adaptation makes a presentation more satifsying to the audience, and you never know: maybe Poe will be the topic for the next Big Read!