Hammock + cool coconut = paradise
With much of the country straddling the equator, Indonesians (and expats) enjoy what many consider to be an ideal climate. Temperatures often hover around the 30° C mark (that's 86°F, for my American readers).
Who needs shade?
Balmy, sun-soaked days during the dry season attract visitors from around the world, while the cool rains of the monsoon season feed the lush vegetation that blankets much of the archipelago's 17,000+ islands.
Jungle trekking, anyone?
AC is an ubiquitous norm, rather than a necessity for most of Indonesia's working population. From pristine beaches to the downtown districts of the country's busiest cities, you'll never be too far away from hawkers selling cool drinks at bargain prices.
The choice of a generation.
Personally, I'm of the opinion that Indonesia's amenable climate plays a large part fostering the local's severely friendly reputation. See "Are Indonesians Really That Friendly?" for more on the greater than average gregarious nature of orang lokal.