I've been thinking about this thread a lot for the past couple of days and have decided to toss in my two cents.
One thing I've learned from the preschoolers the past 6 years is how different they each are. Certainly, there are commonalities. But each child seems to me to be such the individual at even the young age of 4. If you are considering older people, each person has had a myriad of life experiences to contend with. Each person learns differently, at different rates and has different people effecting their lives.
I'd like to throw out my SO's idea of "connectedness." He says that some people have an easier time connecting to others. Some people struggle to connect with others their entire lives. husband is a prime example of being disconnected. People liked him, admired him, and wanted to know him. But, he felt that having connections to others was a curse. From his perspective he felt most at peace when alone.
Basically, what I am thinking at the moment is that the people who are most comfortable in their lives, feel connected to others and valued by them. I've been reading a number of Holocost memoirs lately and what I am learning from them is how people are able to survive inhumane conditions simply by a feeling of connectedness with others. In one man's case, his brother had died but he still felt connected to him. He felt a draw toward a better life in honor of his brother. That feeling kept him alive.
What I see with many difficult child's is that they don't feel connected. Their view gets distorted for a variety reasons and sometimes no amount of love can penetrate that barrier.
I believe that making connections with others (or nuturing) is worthwhile. But we can't expect it to overcome every situation. Some people are entrenched in their behaviors and are simply unable to make changes in their lives.
I am able to help the majority of my preschoolers learn the basics for kindergarten: writing their name, learning the letters, how to interact effectively with the class. But I cannot help all of them. One little guy didn't recognize me two weeks after school was over after I had worked with him 5 days a week for 8 months. I tried my best to help him learn to write his name; he simply couldn't do it. Sometimes even our best effort isn't enough.
Stepping off the cyber-soap-box now . . .