In many situations (daycare, elder care) the caregivers are by no means strangers. My 2 year old spends as much or more time with her daycare teachers and classmates than she does with my wife and I.

They love her and she loves them. Just because they aren't blood doesn't mean they don't play a huge part in her day to day experience and growth. In fact, they play a much larger part in her world than her grandparents or other family that she only sees several times a year.

It feels to easy to dismiss these folks as 'not as good as family' when, at least in my experience, they are much more than just paid baby sitters.