Singapore so hot - Its people ought to be very warm?

"Experiencing Physical Warmth Promotes Interpersonal Warmth" - Williams & Bargh 2008 (Science, 322: 606-607)

"'Warmth' is the most powerful personality trait in social judgment, and attachment theorists have stressed the importance of warm physical contact with caregivers during infancy for healthy relationships in adulthood. ... we hypothesized that experiences of physical warmth (or coldness) would increase feelings of interpersonal warmth (or coldness), without the person’s awareness of this influence. In study 1, participants who briefly held a cup of hot (versus iced) coffee judged a target person as having a 'warmer' personality (generous, caring); in study 2, participants holding a hot (versus cold) therapeutic pad were more likely to choose a gift for a friend instead of for themselves."

See also "Warm Coffee, Warms The Heart Some Say".

Don't jump to conclusions yet though, there may be confounders!