I've learned a few more things about life in a wheelchair. 

Walking is exercise, sitting is not. Walking in public places, whether outdoors in the cold, or indoors in a grocery store, keeps you warm. I am already susceptible to the cold, given my lack of muscle and fat, and not exerting any energy is noticeably colder.

Being lower than everyone sucks. Now I know how dogs feel. My head is at everyone's ass level, which believe me is mostly a bad thing. 

Just because a wheelchair is a chair doesn't mean that all other chairs are obsolete. I can stand and move to another chair, and I probably want to.

Everyone apologizes. Yes, you are in the way. No, you didn't see me. You don't need to apologize like "Oh my god I'm so sorry I must be the only person who didn't see you!" Car accidents result in fewer apologies. 

I feel both hugely conspicuous and invisible at the same time. Some people see me, look me in the eye and acknowledge me, while others seem never to notice me or pretend not to see me. Maybe this is the same for anyone and I'm paranoid. The brain can wander when you're sitting silently, moving through a crowd. Or maybe I'm right to feel different. If you see someone who is an anomaly for one reason or another, maybe you could try to smile and nod instead of looking away. No one needs to feel like a freak.