Physicists and estimation.
Students (the vast majority of whom are engineers and chemists) invariably look at me like I’ve sprouted an extra head when I do dimensional analysis tricks, though, and whenever I assign a problem asking for an estimate, I’m all but guaranteed to get answers reported to all the digits that a calculator can muster, which misses the point.
But I’ve also had this happen even with other faculty from science and engineering departments. I’ve had several meetings where I’ve done some back-of-the-envelope toy model to check the plausibility of something or another, and get baffled stares from everybody else. Or arguments about how the round numbers I used weren’t exact (“But we don’t have 600 students in the first-year class. There are only 587 of them…”) It was a real shock the first time that happened, because I’ve always thought of that as a general science trick, but I’m coming around to the idea that it’s really more of a physicist trick. And maybe, if you’re looking for an explanation of what it means to think like a physicist, specifically, that might be the place to look.
I recall the first time I experienced this, in a physics class in college. The professor gave an answer to a question to within a factor of 2 faster than anyone with a calculator got to the more precise answer, and he explained that in a lot of (informal) cases, a factor of 2 or even order of magnitude would be sufficient — able to rule out possibilities or make a plausibility argument, or even check that you haven’t fat-fingered an answer on your calculator and gotten an obviously wrong answer. He was right, and I’v used the technique quite a bit. Later, in the navy, I heard this estimation technique called “radcon math” — the radiation control folks on a ship/sub care mainly about the order of magnitude of a radiation dose when first assessing a situation, because that tells you the level of urgency should you need to cordon off/evacuate an area. So it’s not just physicists, per se, but it’s plausible estimation is more prevalent in disciplines that do more computation.