All of it, but most particularly PERFUME!
That goes for cologne, too, and air "freshener", and all of those other poisonous things known in America as "fragrance".
What on earth are people thinking? It is one thing to smell clean, but what is the deal with spraying oneself all over with chemical approximations of "fruit" and "flowers", as if that toxic waste smells anything like those things. Bah!
The UK has begun banning a lot of the stuff because it is so toxic, and it triggers migraines and asthma in so many people, and Canada is well-known for fragrance-free policies, but the US is way too in love with the chemical industry to rock their big stinking boat.
I find perfume in restaurants (can't even remember the last time I went to one of those ... maybe a year ago) TOTALLY inconsiderate.
I'd rather sit next to a smoker or a farter - though not next to both, due to the fire hazard.