I remember that I first heard the phrase "desperate people do desperate things" in some made-for-TV movie when I was in junior high. It was said by a high school coach of a team that was losing miserably to explain why he was putting this uncoordinated-freak-always-sits-at-the-end-of-the-bench-loser into the game. I think the kid turned out to have supernatural powers or something, I don't remember.
Anyway, ever since, the phrase has been one of my mental slogans. When I see someone take some drastic action, my first explanatory impulse is to presume they were desperate and then think why they might have been so. It's been especially helpful in understanding some of the weird things I've seen people do in the name of romance, incidentally. Why does [X] keep pursuing [Y] even though it's clear s/he's not interested? It's never going to happen, and it just makes [X] look so desperate. To which I think: but [X] is desperate, so what do you expect her/him to do?
In the past few years, the slogan has morphed into a sequel: "mentally ill people do mentally ill things." The slogan arose from my weariness about hearing people complain about the crazy things done by crazy friends of theirs; or, more specifically, crazy things done by crazy people who had been crazy ever since their friendship began and who perhaps in the first place had been befriended precisely because their craziness made them interesting. But then I would have to listen complain and ask why their crazy friend had to do this particular crazy thing that annoyed them when any normal person would do the normal thing instead. So "mentally ill people do mentally ill things" became a stock reply, intended to reject the idea of speculating about why a person is engaging in some particular instance of abnormal behavior when they have never given any reason to think that they ever approach the world or apprehend reality in anything like a normal way.
Seriously, it's like moving to Antarctica and then whining about how you don't understand why it can't ever just have normal weather.
More recently, as I've been doing all this reading about health care, a third version of the slogan has been forming in my mind. It's current incarnation is "perverse incentives produce perverse results." (Yes! My economist friends would be so proud!) But, really, you see a system that seems altogether twisted in its outcomes, it really is helpful to think: what are the incentives for the people in this system. And, lo, they are often twisted incentives, or at least twisted incentives from the point of view of wanting a nontwisted system as a result.
Of course they're acting desperately, they are desperate. Of course they're acting crazy, they are crazy. Of course the outcomes are perverse, the incentives are perverse. Pathological conditions produce pathological consequences. The pathological conditions are the thing to be puzzled over an explained, rather than acting like the consequences themselves are otherwise genuinely surprising or puzzling. Which isn't to say there aren't real surprises or puzzles: desperate actions by those who have no reason to be desperate, strange behaviors by those who have given no previous reason to expect it, or perverse outcomes from institutions that seem like they should yield better. Or, for that matter: desperate people who do nothing; crazy people who have their moments of complete togetherness; perverse incentives that yield systems that are not nearly so screwed up as one might expect.
* I've also invoked the phrase to explain instances of myself taking drastic action (see here for an example that didn't work or see here for an example that, well, also didn't work). Indeed, I almost see it as a normative theory: if you feel desperate, you should first wait awhile and ponder whether your desperation is truly justified, but then, if you are still desperate, why aren't you taking drastic action?