Dog poo on the ground.
I can't go into my own garden because I am so frightened that there is dog poo there. It's ridiculous.
I get extremely anxious if there is a poo on the ground and I have to walk near it.
I obsess about a poo I see on the street, especially if it is there for more than a day.
The irony of this is that I work as a professional dog walker and have no problem cleaning up after the dogs I walk.
I am a dog owner too and, again, have no problem cleaning up after my dogs.
I am anxious about the cat litter tray in my house. If there is a poo in it, I dispose of it immediately. In the night, if I visit the bathroom, I avoid looking at the cat tray in case there is a poo there.
It's old poos that terrify me.
I also hate heights.
I had, until a few years ago, a phobia of people vomiting. It started when, as a child, I heard my mother vomiting and screaming afterwards. I had a panic attack, some years later, when my brother vomited. My mother slapped my face, which made the experience worse. I think I was cured of that phobia after my then toddler had a vomiting virus.