I've never come across a perfume that made me want to retch but almost anything that is purely floral gives me a horrible headache within seconds. I don't even have to have smelled it up close; it happens just walking by someone wearing too much or past a perfume counter.
Also, I can't be the only one who gets really irritated with how hard it is to actually smell/buy perfume or fragrances in stores. Sephora isn't so bad because they keep out the coffee beans (though I sometimes swear they've expired and smell like nothing) and most of the time sales staff and customers aren't openly spritzing stuff everywhere, but other places like Bath & Body Works, Victoria's Secret, Lush, etc.. I can never tell if what I'm smelling is actually the thing I'm trying to smell, or if it's a combination of that and something else in the air. It's super frustrating to buy something you think smells really good, only to get home and discover it does not. This happened with a Tokyo Milk perfume.. I thought it was the perfect amount of floral/spice/fresh, but when I got home it's like I had some bizarre evil twin perfume instead. The boutique had a lot of open fragrance samples, plus candles, plus possibly just dosing the air with scent, so who knows what it was that I actually liked. :s