Your rectum is fairly airtight is my guess, boxes not so much. Can’t believe that’s a sentence I’ve now typed.

They still stink if you let some air through by farting. Boxes are rarely airtight, whereas assholes usually are.

Source: I have a plastic box that I often put some acetone in. And sometimes I fart. The two are not related.

They do. You just aren't inside yourself.

Your asshole isn’t just open all the time. And even then, there are a couple of gates (sphincters) that prevent a straight through passage from your bowels to the outside of your body.

Sphincters and seals: they do a good job! Not fun to think about, but that's why when someone shits their pants, or dies and voids their bowels, it's immediately obvious.

If your body was like a shoe box you would bleed to death. put shit in a ziplock back and then a cooler and you would be hard pressed to notice a smell for days.

I appreciate your presence on this website a lot and that's a genuine sentiment. Most of your other posts are pretty bleak (and I appreciate them too) but this one got a good giggle out of me xD "Why" lol

Hold on, you all don't smell like shit too?

If you leave your mouth open for long enough, you break the vacuum holding the shit and piss stink in and you'll start smelling.

When you're dead I'm sure it will be noticeable.

Use an airtight box??

Not smelling like excrement would have been a significant advantage for most of human history & our ancestors before that where we had predators hunting us and conflicts with other humans where hiding would have been a good defense tactic. Animals that do have strong scent usual are a deterrent for predators or territorial predators marking their territory.