My Crappy Answer

There is nothing more important in the world than shit.

Shit is life, shit is culture, shit is language.

Shitting means you have eaten, a sign your body still wants to live.

Not shitting for a long time is fiercely painful. Shitting too much chaps your anus raw.

If you don't shit, you die. If you shit too much, you also die.

If animals didn't shit, plants would die from no fertilizer, causing a collapse in the food chain. From no shit.

Not shitting where you eat is sound logic in both senses, literal and metaphorical. You are not meant to eat shit, and its smell and exit point are meant to prevent coprophagia. And unless you work at Trader Joe's (allegedly) you shouldn't shit where you eat (meaning don't fuck your co-workers as it can cause drama if things go to shit). No shit.

Your shit can indicate if you're healthy, and varies according to your diet and exercise.

People who do not eat vegetables shit for longer, less often, and more painfully than people who do eat roughage.

Shitting in your pants is the most embarrassing bodily fluid release one can suffer from socially. Tears, earwax, mucus, piss, even sex fluids, all pale before a big brown shit stain leaking through your pants.

In English, the word has become a noun, a verb, and has an adjectival and adverbial form: shit, shit, shitty, shittily; and its usual exclamatory function: Shit! Shit! Shit!

I shit you not.