Each individual person will have their own individual reasons for why they may have come back to Malaysia.

- Sometimes it may be "the grass is not greener", but this is only one reason.

- Sometimes they miss their families, their language, the familiar sights and sounds of a culture they grew up with

- Sometimes they've earned enough money overseas and want to invest that money in a business back home due to the exchange rate.

Why don't you go about and ask each person who does go back, and compile a list of answers, then come here and show us the research. It would be interesting to see a % value on the reasons that are generally given. If you're stringent enough, you might even get that research published in a business journal.