Allergies can make you more sensitive to the things you're allergic to. I have often completely choked up from the REEK of someone's perfume, only to find out that not only does the person not smell it, but that non allergy-sufferers don't smell it at all!

As for the smokers clustering outside the doors - you're lucky. Smokers in Orillia seem to smoke outside the door of a non-smoking building with the door open letting all that wonderful stuff into the building anyway. Before all the anti-smoking laws, all the smokers were inside, and all you had to do to stay away from them was not go inside. Now they're stinking up the streets and you can't go anywhere without choking.

I stopped singing in church choir because of the Easter lilies, I can smell it from the moment they're placed in the building to 2 months afterwards. I can't sing. Not much point going to church...

Synthetics are much worse than natural oils, but that depends on a person's allergies.
Considering that allergies were originally caused by industrial pollution, I would not want to wear synthetic perfumes, even if I didn't have allergies.

Lawn spray is really awful too.