The size of the economy very directly impacts people's quality of life.

I agree, but not necessarily at fostering happiness!

Look at the countries that are generally regarded as happiest: are their economies the biggest?

> Look at the countries that are generally regarded as happiest: are their economies the biggest?

Assuming when you say "biggest" you mean per capita... yes. Obviously it's not the only factor, but generally I think it's generally accepted that people in rich countries are better off than people in poor countries.

"size of the economy": Do you mean total GDP, or GDP per capita?

Per capita

Why is your original comment downvoted? It makes no sense to me. This is simply common sense. Most of the very high quality places to live are also wealthy, highly developed countries.

No idea. I try not to worry about downvotes on this site.