Once again I come to MO for help with something I'm writing for the public.

Which habits of mathematicians -- aspects of the way we approach problems, the way we argue, the way we function as a community, the way we decide on our goals, whatever -- would you recommend that non-mathematicians adopt, at least in certain contexts?

In other words: if you can imagine a situation in which someone came to you for advice, and you said, "Look, I think you should be a little more like a mathematician about this and...." what would be the end of the sentence?