The inimitable Hans Rosling[1] used to call himself a "possibilist": People often call me an optimist, because I show them the enormous progress they didn't know about. That makes me angry. I'm not an optimist. That makes me sound naive. I'm a very serious “possibilist”. That's something I made up. It means someone who neither hopes without reason, nor fears without reason, someone who constantly resists the overdram…
This is a great quote. I'm probably going to be using that example in a lot of debates :-) Thank you!
There are so many better examples to choose from that don't strike a personal nerve (at least, personal to this extent) with any of the audience. Or if your audience hasn't had this experience, it's a moot example that they can't really relate to.