I cannot stand when someone breathes through their nose loudly. I want to scream, open your mouth already! It is my biggest pet peeve ever! I also hate slurping! No matter what it is, don't be slurping food.
I'm just the opposite on breathing. I hate when people are heavy mouth breathers. It makes my mouth go dry in sympathy. Slurping I can handle. I can't handle loud smacking noises. Each bite you take doesn't require a loud smack of the lips