Of the 5 senses (sight, taste, touch, smell, hearing), my sight is downright dismal, my taste is normal as far as I can tell, hearing is still decent so long as I don't overuse my earphones, touch still up to snuff, but smell, oh my. I can sniff out cigarette smoke that no one else notices, pick out a lack of natural perfume in a rose, and can remember someone by their smell.
I have memories revolving around aromas or stenches. Going to a multi-race school, we had our share of people from all over the world with their own cultural perspective on cleanliness. One day playing soccer, I accidentally rushed a classmate from the Middle East. I don't know if I hit him, but recall the horror realizing that my hand smelled of BO. I had to take a break and wash it with soap and water; could still sniff it out some hours later, that's how bad it was. It was on par with the intense, oily odor of my 2 day roommate during a conference in Philadelphia; she was from a small Western African country, and I had serious breathing problems after the first night we shared in the hotel. I also feared that the smell was settling into my own clothes, and was very grateful when at the next stop I had a single room to myself.
My sister's boyfriends soon learned that if they wanted to get on her family's good side, they would have to contend with a younger sister who was forced to chaperone them on certain events. Imagine being dragged out from doing what you want to do just because your mother/father said "go with your sister and that boy. Make sure nothing happens." ARRGGGH. The boys in question soon learned that I would put in a positive vote if they had nice smelling cars, didn't smoke (at least not around me), and brought roses that were naturally fragrant. Points removed for short stemmed wimpy flowers with not a note of perfume.
I once joked with friends about a date who had no smell. Which might be a good thing for the most part. But when someone smells more like, water? or air? it's a bit disconcerting. Makes me think he's something out of the book Perfume by Patrick Suskind. The main character is a murderer who has no smell and at the same time the most sophisticated sense of smell; the trait allows him to avoid detection, and his keen sense of what a perfume is made of makes him very rich. As for my date, you can't have any memories of a person without some sort of fleeting spectre of themselves attached via your nasal passages I think. Preferably a good smell, like chocolate!
There are cultural differences about cleanliness and body smells. On this interesting snippet from a book by Katherine Ashenburg, she writes about her research on the historical differences of washing, bathing, deodorants, hygiene, and ultimately smells. While she notes that modern day Americans are crazy about bathing and deodorant, former colleagues of mine would agree that we had our share of questionable American visitors, who we called "plucked from the gubat (forest)" for their insidious stink. The most notorious of recent years included one research fellow who wore the same pants every day for a month (we'd ask each other as we guided him from lecture to lecture when he'd ever change clothes). There was never a year that we didn't have at least one who we'd wish we could dunk in boiling hot water and a lot of soap.