my annoyance and my response varies on my mood.

If a child asks it is usually because they are genuinely curious or scared. They just want a simple answer. The parents usually are mortified LOL. I just say I use X to help me walk/get around because my legs don't work right. They often want to know of it hurts - I always say "not really" so they aren't frightened of people that are different. I will relate my sticks or wc to their sister's stroller or the child's glasses.

Adults/strangers asking: depend on how they asked and my mood. If a stranger says "What's wrong with you?" I will give a sharp look and a smartas* answer like "Shark attack". Often I simply reply with a snippy "Why do you need to know?!?" then I move on.

If I know the person and they seem sympathetic and curious I say I can't walk well or have a neuro problem. I rarely reveal my medical details to anyone but very close friends/family. After all, I don't ask about their medical issues unless I genuinely care about the person and want to help.

I probably give some smart remark answer too often but this is personal, ya know? I guess we as a society went from whispered curiosity & looking away to the the bold & uninhibited.