My super sensitive smell and taste do my head in.
My boyfriend loves spicy food but if I come within about 20 metres of it the mere smell makes my eyes water. We also have a very stinky dog that doesn't seem to bother anyone else. I can't go anywhere near perfume, public toilets, take aways, buses etc without feeling uncomfortable because of the overbearing smell.
Probably the most common problem I have is with milk, as if it's even slightly off (which usually means it's 2-3 days old) it makes me retch. I have to smell it every time I pour it over my cereal as I've had to chuck out perfectly good bran flakes because the milk tastes so bad.
The positives are that I always know if someone has left the gas on, and I can detect when a newly baked cake has been made well before it comes out of the oven.