I agree. You can know them well-enough for practical purposes; sometimes they will surprise you.

As an aside, I think the antonym of "lonely" is "understood", and when you empathize with someone, you put yourself in their position and feel understood, and thus less lonely.

  A person can feel lonely in a crowd
  but not alone when their self is understood
  even when alone in a cell 
  made of all (flesh, concrete or abstract)
  that barriers can be built of.