Post things you've noticed about yourself. Over the years, I've gotten the impression that most people are largely oblivious to what's going on with their own minds and bodies. Once, while drinking in a bar, I mentioned to a girl that alcohol makes my lips numb, and she was surprised to find that it made hers numb too; she'd never noticed before.
Other things I've noticed:
When I'm dehydrated, my heart and pulse are much more noticeable, to the point of being intrusive. My eyes get dry and bloodshot when I'm tired. Salt makes me pee more. My ability to produce body heat is greatly reduced when I'm hungry. Moderate doses of alcohol have a powerful analgesic effect on me (which I demonstrated once by holding a flame directly under my left forearm for 5 seconds; I didn't feel any pain at all, and I still have a scar from it). Capsaicin irritates my intestines. Often my brain stalls and puts me into a semi-lucid, inattentive state for 5-10 seconds (my mum has the same problem, but she's not aware of it unless I point it out to her, while I'm always aware that it's happening). Grapefruit makes my lips tingle. Kiwi fruit makes my tongue sore.