Anywhere from a few days to a week before my period starts, my body odor slightly changes, which in my case means that I acquire a bit of one whereas usually my sweat smells of pure salt water.* This in and of itself is not weird -- hormonal changes and all. (I'm glad I seem to have mostly grown out of the whole "tender nipples" thing -- that can get owie.)
What is weird is that it's usually only the left armpit, not both.
WTF body?
* Another one for the quirks list, I guess: Under normal conditions I only shower once a week, and that's because my hair is starting to get oily and uncooperative. I can go about ten days before I feel like my body needs washing, aside from my hands and face. I almost never wear deodorant and, though I know this goes against the "toss cosmetics after six months" rule, have literally been working on the same stick for years because I wear it so rarely. This characteristic would seem to be genetic, as neither of my parents smells like much of anything either.