Generally speaking though, it's less a matter of reasoning with them as it is a matter of finding the right buttons to push. Is it that their goals are misaligned from yours? Phrase your response in terms of their goals; they can't be too out of line if they need something from you. Do they not trust you? Point out that they're going to have to trust you whether you do it your way or theirs.

If they're being genuinely unreasonable and out of touch with reality and they are completely unwilling to change their approach, I'd personally rather spend my time finding ways to not have to work with them. Chances are they really aren't though. They just have a different way of looking at things that you can't meet without learning to think like they do a bit.