I wrote a piece a while back along a similar line to yours in terms of people from industrialized nation’s in general and America in particular being rich. I think I used a lot of example relating to food:

• I wonder what percent of people that have ever lived have had the privilege of eating at a restaurant?
• For most of human history all you needed to know about nutrition could be summed up in just two words: eat more. In America, almost everyone (including myself) needs to be told to eat less. That’s crazy.

I also really like the tension you’re striking here. Yes, we should be grateful for what we have, yes, we should pursue our own happiness, and yes, we should also take our eyes off ourselves to help others. More or less in that order.