I think it's wonderful because it seems to be populated by a bunch of caring, helpful, intelligent, thoughtful and witty people.
Above all for me, it's the witty bit that does it: that unnecessary humour that makes the many discussions on here entertaining and brings a smile to my face.
For example... Today, in the discussion about who cycled to work, the image of Smudge removing shoes and socks to do maths was uncalled for and totally irrelevant, but it was beautifully done. That's what makes it wonderful for me.
How was it for you?