"Every country in the world which the UN judge to have standards of quality of life all have something in common. LOW POPULATION DENSITY."
Erm, no, patently and obviously false.
I presume you're talking about the UN Human Development Index Score?
"The Human Development Index (HDI) is a comparative measure of life expectancy, literacy, education and standards of living for countries worldwide. It is a standard means of measuring well-being, especially child welfare."
The average population per square mile for the top and bottom ten countries by that rating are:
Top 10: 259.6
Bottom 10: 141.05
So if you're going to argue anything the conclusion seems to be that a high population density leads to a higher HDI score.
Though I actually doubt that there's much of a connection at all. There's a spread of densities in both the top and bottom 10s and I don't think that there's much to be proven that way.
I'm not saying that we're not heading towards being overcrowded, just that density and HDI are not directly connected.
For those interested in doing the maths themselves here are the top 10 countries and their populations per square mile:
Norway 31
Australia 7.3
New Zealand 41.6
United States 87.4
Ireland 164.2
Liechtenstein 572
Netherlands 1,037.90
Canada 8.3
Sweden 53.3
Germany 593
And the bottom 10:
Mali 30.3
Burkina Faso 148.9
Liberia 92
Chad 20.8
Guinea-Bissau 44.1
Mozambique 74.3
Burundi 836
Niger 31.2
Democratic Republic of Congo 75.9
Zimbabwe 57