Hilarious article about the usage of "shit": shit
Under usage I quote:
"In the word's literal sense, it has a rather small range of common usages. An unspecified or collective occurrence of feces is generally shit or some shit; a single deposit of feces is sometimes a shit or a piece of shit, and to defecate is to shit, or to take a shit. While it is common to speak of shit as existing in a pile, a load, a hunk and other quantities and configurations, such expressions flourish most strongly in the figurative. For practical purposes, when actual defecation and excreta are spoken of in English, it is either through creative euphemism or with a vague and fairly rigid literalism. Substitutes for the word shit in English include sugar and shoot."
"Shit denotes trouble, as in I was in a lot of shit; low quality, as in That disk drive is shit (see "piece of shit" below); unpleasantness, as in Those pants look like shit, or This brown stuff tastes a bit like shit; or falsehood or insincerity, as in Don't give me that shit or You're full of shit, or surprised anger, as in Jim is totally going to flip his shit when he sees that we wrecked his marriage. Sometimes using shit to denote anger will be heard in the phrase shit a brick. The word bullshit also denotes false or insincere discourse. (Horseshit is roughly equivalent, while chickenshit means cowardly, batshit indicates a person is crazy, and going apeshit indicates a person is entering a state of high excitement or unbridled rage.). Are you shitting me!? is a question sometimes given in response to an incredible assertion. An answer that reasserts the veracity of the claim is, I shit you not."
"The expression no shit? (a contraction of no bullshit?) is used in response to a statement that is extraordinary or hard to believe. Alternatively the maker of the hard-to-believe statement may add "no shit" to reinforce the sincerity or truthfulness of their statement, particularly in response to someone expressing disbelief at their statement. "No shit" is also used sarcastically in response to a statement of the obvious, as in No shit, Sherlock."
... and it goes on and on and on....