The smell of coffee. I don't know what's wrong with me (or alternatively the vast majority of people) but it smells as disgusting to me as a steaming pile of dog poop. I learned to ignore it to some extend but I still hate it in all its variations: The powder, freshly roasted beans, freshly brewed coffee, cold coffee, coffee breath, ...
That must not have been an easy thing to do, and I feel for you knowing how omnipresent coffee is. Heck, I had my first coffee I was not 9 year-old. I remember it vividly, it was a large and thick cup (to my kid eyes at least) half filled with black coffee (not the tinted water many people erroneously call 'coffee'), without milk but with sugar, way too many. I liked it, probably because of the too many sugar in it, and I never quit drinking coffee for 50 years or so, up until very recently and only because my doctor told me so.
As for the smell, obviously I would not compare it to poop like you did but I reckon there is one thing they may both remotely share, very remotely though, a kind of 'earthy' smell?
Maybe I phrased it in a confusing way. Coffee does not smell like dog poop to me. It's just exactly as disgusting. Can't really compare it to anything else but it's a very intense smell that I just can't stand. I noticed that microwaving chocolate milk can lead to a similar smell but by far not as bad as coffee.
It's not roasted stuff in general that I despise and also not related to milk.
It is amazing how much this kind of thing depends on conditioning; there is a culture I read about recently where if someone sees you drinking coffee then they would ask you how you were feeling because it is considered to be a gross drink that you would only have when you were sick; tea would be the beverage of choice at all other times.