"The science behind our personal fart preferences is pretty simple. We like things (all sorts of things) that are familiar. And the microbes that make our breath, sweat, and gas smell foul to others are pretty dang familiar to us."

https://www.washingtonpost.com/news/speaking-of-science/wp/2014/11/10/why-we-dont-think-our-own-farts-stink/