I remember studying Maslow's Hierarchy of Human Needs many years ago at university.
Maslow (a psychologist) put forward that all humans strive to achieve a number of human needs.
In general we strive to fulfill some of these needs before others.
We first aim to have enough food and shelter. Once we have these things we strive for material possessions to add to our comfort.
Once we have these things we look to achieve goals which give us a sense of accomplishment.
The problem is that even after we achieved all of these things our happiness tends to decrease after a short time and we are again unhappy.
For whatever reason we are programmed never to be satisfied.
However, on the positive side, we do have rational thought we can use to overcome the feelings of unhappiness we have.
If we make an effort to realise how much we have (food, shelter, friends, family) then we can overcome our unhappiness.
As the Bible says "give thanks to the Lord for what you have been given" - and get some perspective.
