Grass is always burnt on our side!!

I happened to chance on an ex-TCS colleague after lunch today. He left TCS to join a well-known MNC about the same time as I left for my MBA. Now we work in the same campus, but different companies. One topic led to the other and he revealed that he would be interested in joining another company because he thought there were better opportunities there. I said to him very casually, Grass is always greener on the other side mate. I wasn't prepared for his reply. He said not only is grass greener on the forward looking side, it is also greener in retrospect i.e once you jump to a new job, the former employer starts looking better. My prompt reply was, 'maybe grass is not really greener on either side, its just burnt on our side! It was supposed to be a joke and rightfully so we burst out laughing. The seriousness of what I had said started creeping in only when I was walking back to office.
We always think what we have is inferior to what others have; that there are better opportunities elsewhere. We do not realize the opportunities we have to make our current situation better rather than keep fantasizing about a better future. This is not to suggest that one should be content with what he has simply because its the same everywhere else. Doing so would be the end of our personal growth.
All I am saying is that one should objectively evaluate the existing situation and compare it with available options. Greed needs to be out of the equation for this objective evaluation to work.