Biometrics:
A slight variation of the situation you describe was the beginning of the end for me. I was out in service with Dad and came to a door that was answered by one of my classmates. He was cool; he didn't tell anyone about it. But that day, I decided that I would never go out in service again. I never did, and shortly after I stopped going out in service, I stopped attending meetings as well.
I had a slight variation on my car experience. When I was in year 5 at school I had a crush on this girl in my class. For months I avoided going witnessing near her house. Whenever a map of her area came out I would cringe. I even faked twisting my ankle once.
I thought everyting was going well. I even got the courage to tell her I liked her (through a friend). And she said she liked me. I guess it must have been my first crush.
One saturday I was in the field service a long way from her house. The house we knocked on was that of her (ugly, loud mouth) best friend. Monday at school, in front of everyone, she said in a loud voice "don't EVER come knocking at my door again. We don't want your religion ... And by the way [crush's name] doesn't like you". It was one of those moments that defines your life. Or what's left of it.