Because some people don't want to live comfortable lives. They want a bit of adventure and danger.
Don't bullshit...a few of my closet buddies left not on what you have said, to Canada, Australia, NZ...the list of reason is so common, I would not even want to mention. You don't have to 'suck eggs' that much, what PAP had done for us under the sun, we all know to a "T". We have a clean environment, green too, efficient transport system, safe to some extent, a fairly clean & proficient government but not efficient, good healthcare system, housing, infrastructure, etc.. I come from the time, when PAP was an opposition to where we are today..in the words of the older people, can consider to have 'eaten more salt than rice', tasted the bitters from the sweet & sweated my guts out for a living & still is working hard.
It is not the comfortable life, we are too comfortable, or the sense of adventure & freedom...it is more than that. Please don't 'suck eggs' that much, a spade is a spade..PAP is good to a "T", I would not even deny..to praise them to the ends of the earth..hmmm