I just introduced a conservative coworker ("we need K-12 education to be privatized!") to the economic theory that private markets don't work as well as collective sponsorship of goods in situations where there is very, very little control over who gets the benefits of the good (no matter who paid for the good).

"Wow. That's very interesting. I'd never heard of that before."

My jaw just about dropped to the floor that he could be so opinionated on privatization without anyone having ever mentioned external benefits, but hey...it was kind of fun to get to be the one. :-)

I hope it sticks.