If it smells like shit it's probably shit

My simple variant of Occam's Razor.

Works well in life, business, engineering, relationships.

The risk in using this principle is deluding yourself with confirmation bias. Hence, the "probably."

But let's be real, most of the time shit smell = shit. And you save time, energy, and resources by not dwelling on whether the shit-smelling thing is shit or not.

Another way to think about it is, at the very least, a shit-like smell is indicative of someone's comfort with producing a shit-like smell (or incompetence at avoiding such a smell), in which case the actual presence (or not) of shit is irrelevant - I just don't want to smell it, think about it, taste it, be near it, or have anything to do with it. Real shit or not.

By following this principle, in the worst case you will misidentify shit and perhaps miss a non-shit opportunity. But your gut is intelligent, and most of the time you will have correctly identified shit and saved yourself from the endless, emotionally expensive, wasteful experience of dwelling on whether or not the fumes that smell like shit are indeed the result of shit.

And if you're still unsure, consider: if false-positives are less risky than false-negatives, the most logical course of action is to assume it is indeed shit and move on to greener, less-shitty pastures.

If it smells like shit, it is probably shit. Avoid it, get rid of it, move on.