Things that disgust me, in ascending order:
1. People brushing their teeth in the work bathroom.
2. People flossing in the work bathroom.
3. The spatter of toothpaste and crud on the mirror that persists for the rest of the day due to people brushing and flossing in the work bathroom.
It's not that I want your teeth to rot; it's just that I'd rather not be a spectator in the process.