metal detectors

Racism, bigotry.

Health or other claims that companies make related to foods that are so obviously meaningless yet people still fall for them.

"Farm raised chicken" - any place that raises chickens is inherently a farm.
"Organic maple syrup" - all maple syrup is organic.
"Natural sea salt" - table salt is chemically identical no matter where it comes from and the word "natural" means nothing here.

I also see this the other way as well:
"Cola takes the rust off nails" - has nothing to do with how healthy it is. Any acidic food, healthy or not, will do the same.
"X food is loaded with chemicals" - everything is chemicals

Complete strangers who ask me what my pet peeves are and other personal info/beliefs/preferences.

ink

Kids on my grass
Ice cubes
Jello

food noises, advice from strangers/losers, ppl who complain a lot

Other people's spreadsheets. Especially when they think they're really good at Excel.

People whom ask what my pet peeves are.