In my defence, I may have personal space issues. Then I get really agitated if some one is standing behind me and I can feel there breath on my neck or head.
People spitting in the street also annoys me as it is disgusting and spreads disease.
$5000 in Singapore for spitting in the street.
I'm not a clean freak but singapore is only place I've been so far where i didnt have to check where i sat or put my hands etc
Don't forget to wash your hands after (not actually) slapping them.