http://edition.cnn.com/2012/12/21/world/asia/singapore-least...
Singapore is also multiethnic, but it's quite resolutely not a melting pot. The heavy hand of the government is keeping a lid on a lot of tensions, not all of them obvious to the casual observer (Singapore-born Chinese vs mainland Chinese, etc).
Last and not least, Singapore's wealth distribution is extremely unequal. It scores well on raw GDP per capita etc, but the poorer parts of society compete directly with foreign labor working in slave-like conditions(+), and thus work extremely hard for paltry salaries.
(+) Quite literally, especially in the case of maids: it's not uncommon for them to be on duty 24/7/365, not allowed means of communication and physically locked inside the home when their masters are away.
The Singaporean government ships!
I mean would you rather a) work at a company with very relaxed policy, beers at lunch, a really friendly boss, low pay, and where no work ever ends up being completed and you don't learn much or b) work at a company with a few policies you don't agree with (like drug testing) and a boss who is a bit of a jerk but you do important work, you learn a lot, you earn a lot, and your boss tries to help your career?