Puzzled by people's puzzled reaction to my presence.

I've been going over in my head, thinking about three very similar incidents that happened years apart, and I still don't understand them. Perhaps people here can help me.

  1. I was around 16 and walking along a street around 2 or 3 minutes from where I live.  I unexpectedly came across an  acquaintance from school.  He was very very puzzled when he saw me, asking me what I was doing around here. He looked even more puzzled when I told him I lived in the next street.( He was just visiting his grandmother, so didn't live there)
  2. About five years later, I was living elsewhere.  A work colleague had seen me the previous day, while driving, now she was asking me, " we saw you yesterday on ***** lane, you were out of your way weren't you?  What were you doing around there?". I told her that I lived there.  Once again the reaction was astonishment/very puzzled.
  3. Ten years later a repeat performance, work colleagues saw me from a passing car and wanted to know the next day, why I was walking in that area.  And again I was a couple of minutes from home.

Unfortunately, I never followed up the conversation with these people and never asked them why they were so puzzled by my presence.