I feel that a culture of no refund/no exchange policy in the retail industry, as is the case for Singapore and many other countries, is a short sighted one. Consumers quickly learn to be very cautious, and doing lots of bargaining hunting before committing to buy anything. In contrast, a generous refund/exchange policy encourages consumers to let their guards down and they end up buying more, thinking "I can always exchange it or get a refund if I don't really like it".
Sure, sometimes they end up doing that, but often, after a while, they decide that it's too much hassle, or they don't have the time, or the product is not too bad after all. Just look at the enormous consumer debt the US has accumulated, due in no small part to the very generous refund/return policiy of US retailers.