Like someone else mentioned, it's the artificial scents that are bad. At least for me. It's not the smell that is the problem, but the toxicity.
We get a lot of cars running over skunks around here, and it seems like at least once a week, the smell of skunk comes wafting in through the window. That doesn't bother me all that much. But when the neighbors are doing laundry, I have to close the windows or I get a headache. I think it's those scented drier sheets. Why can't people just accept the smell of clean clothes? It's not as if there is a stench to cover up; the clothes are flipping clean! Why the overpowering chemical perfumes?
On the other hand, natural scents are just fine with me.
As far as perfumes go, one of the worst offenders is Calvin Klein. I rarely open the types of magazines that advertise that stuff, but once in a while you are in a waiting room, and want to read something. So you open up whatever magazine is lying there, and there is a sample card from Obsession or something. Aaaaccckkk!! ! Instant chemical headache, right between the eyes.