As a hygiene/clean freak, the sense that makes me most uncomfortable is smell. Let me explain. You smell something icky. You know that the only way for you to smell something icky is by your brain receiving a piece of ickiness to interpret. Which means a piece of ickiness somehow gets inside of you without you being able to control it. The very thought of that makes me want to curl up under a cover and never leave my house again.
I decided to find out just how the olfactory system - the system of the sense of smell - works. There are a number of different articles out there explaining it excellently. Volatile (easy to evaporate) substances release molecules that float around in the air which enter your nose and latch onto neurons (nerve cells). This is why you can smell, say, food and not metal. Metal isn't volatile. Additionally, not everyone can smell everything. If your DNA says you can't smell camphor, then your brain won't be able to interpret that smell.
A signal is then sent to your brain so that you can figure out what the smell is. Absolutely terrifying isn't it? Think of all of the things that get collected in your nose until they're flushed out as snot. Actually don't. :(
In order to make myself feel better, I made a diagram explaining how *my* olfactory system works. If I keep telling myself that Narty the Neuron Gremlin gets lonely sitting inside my nose, then I won't feel so bad being able to smell nasty things:
As much as molecules of ickiness flying up my nose creeps me out, I wouldn't do away with smell. There are so many pleasant things to smell out there, and many are attached to sweet memories. Fresh laundry. Warm pancakes. Eucalyptus.
There are certain smells that make me remember random things from my childhood. Like the smell of freshly baked muffins. My aunt used to make them whenever I slept over at her place. She'd bake them in such a way that they'd be the first thing we'd smell when we woke up. My cousin and I would then race kicking-and-screaming downstairs to the kitchen, somehow convinced that the second one to reach wouldn't get any muffins...
What are some of your childhood smells?
Nose image taken from here.