I spent years not being able to smell anything at all. When I was a teenager, my doctor had me do an allergy elimination diet. After a couple of weeks, my sense of smell suddenly returned. My asthma went away, as well. It turned out, I was allergic to milk, and my allergy had dampened my senses of taste and smell.
Scents can invoke memories, emotions, and attractions. Odors that attract one person may repulse another because of differences in perception and memory association. Pheromones are the root of attraction for many species.
The sense of smell can even be life-saving. If you smell natural gas, you know something is wrong. People with seafood allergies know to leave the area if they smell fish cooking. Fish particles floating around the air are enough to send people with severe allergies into asthma attacks.
Some of my favorite scents are lavender, honeysuckle, cedar, and fresh bread. Cedar is a memory-invoking smell. We had cedar trees in the yard of my childhood home, and they were plentiful in the forests surrounding my town. I hate patchouli and artificial scents, especially perfumes, which make me feel sick. I have a violent reaction to the smell of bacon -- it is absolutely nauseating and often makes me vomit.
So, what are your favorite and least favorite smells? Are there any memories invoked by exposure to them?