system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does my poop smell fine to me, but it smells terrible to other people?

It usually smells okay for about 10 minutes, and then after than it starts to smell like anyone else's poop. Farts apply here as well.
gpt
Our sense of disgust is a way to stop us getting bad germs in to our bodies. This is why we don't drink gone off milk. Our noses are pretty good at telling us what is bad and what is good hence why we can smell whether food is good or bad. 

This sense is triggered when smelling a fart. Only the understanding that it was your fart puts you at ease from being disgusted. Since if it came from you it's less likely to have germs that weren't in you already. 

A great test for this is when two people fart silently at the same time. Both are comfortable with the smell only till they realize someone else farted.