The smell of death (when someone is about to die).

While I have been assured that if I had forced my friend to a hospital 6 hours sooner than he got there, he still wouldn't have survived, I still carry thay weight on me wondering "what if" I had forced him to the hospital as soon as I told him he smelled like death.

Maybe not that interesting but whatever. I used to live in a student corridor with a common kitchen. We shared 2 refrigerators and one freezer, having a couple of shelves each. Since there was pretty high turnover, people moved in then moved out, we didn't really keep good track of stuff. I found several years old food in the freezer for example that must have been owned by someone who moved out long ago. Anyway, there was a mysterious 3rd refrigerator too which I had not seen anyone use or even mention. One day I decided to check out what was inside it. I opened it, for about 1 second, an unholy yellow substance started to flow out of it, closed it. I was shocked how anything could smell that intense, whole kitchen and corridor was filled by the stench. Seems like that refrigerator had been off for a long time (months, years?) with food inside it.

Tragedy of the commons. A reminder that communism poisons everything even your nostrils.

bacon

the smell of a mountain meadow at sunrise

The smell of tonsil stones. Death, disease, putrid, all together when you crush one.

Guava tree fruit. You leave it on the counter and then it fills up the entire room with the sweet scent. For that reason it was an annoyance. I don't want a fruity room.

I have no sense of smell. The condition is called asnomia. Because the symptoms are not visible, no one considers it a disability. It doesn't even pass a spell check and if you google it, it "corrects" it to insomnia. An example of how it affects me is that I cannot eat seafood because I can't smell if it is bad. It is common for restaurants to unintentionally serve a bad clam, oyster or mussel but most people immediately can tell. I find out a couple hours later when I become violently ill. I love seafood, but had to give it up because the punishment for failure was too high.

Not technically the most interesting but the smell of shit if it's in a container then opened like a week later. You literally can not even exist in the same space. You just start gagging.

Once, I smelled cancer on my skin. I didn't realize that's what it was until I was later diagnosed with skin cancer in that same spot. That explains how dogs can be trained to detect cancers in people by smell. But I don't know how it would work for internal cancers.

EDIT: I just searched, and found stories that dogs detect human cancers in urine, sweat and blood.

Fresh deer taint. Its terrible when it hits your nose, like musky BO piss, dry shit, and dirt. Its such a unique and powerful smell. I've associated Its earthy pheromone laden stink with really good memories, so I love it, and it makes me happy to think about the smell of deer taint.