What does Gene mean when he states that one of Finny's reasons for living was "a flow of simple, unregulated friendliness" between people?

If you look at the entire quote in context, you'll see that this quote is actually a description of Finny, which alludes to his carefree, friendliness and ability to give those around him a sense of peace. Finny saw this simple friendliness as his purpose and reason for living.