Common dust, pollen, rag weed, grass (all 5 variants
) everything that a cedar tree produces. Aspirin, and all aspirin related pain relievers. Smelly, stinky people that only bathe once a week in dirty water, and has no idea what deodarnt, a tooth brush and paste, or soap is.
The thing that causes me the most irritation is: Some good samartian who drives at the same speed as all other lanes, while in the left lane!