"Eat your own dog-food and smell your own farts" is just crass enough that people will actually remember and retell it. Nice work by the author's Comparative Memetics Division.

"Eat your own dog food" == experience your own product.

"Smell your own farts" == experience your entire product, including things that are typically unmentionables like customer service and billing

The phrase is striking but doesn't make a whole lot of sense to me.

Companies make dogfood and sell it and expect others (dogs, who aren't known for verbalizing dissatisfaction with their food) to consume it. The producers of dogfood don't really care what it tastes like or how nutritious it is.

But I can't imaging a business which involves collecting farts and selling them to others and where sniffing a small quantity of each bottled fart would help improve production processes to ensure a better experience for the customer. And most people are appalled at the smell of others' farts but can tolerate their own, so the "smell your own" test wouldn't really tell you anything.

It doesn’t work here because “sniff your own farts” is already an idiom that means “believe your own bullshit” - aka delusional.

Eating your own dogfood is laudable - sniffing your own farts is not.