Siestas are important in the tropics, if you don't want to fall victim to heat exhaustion, or worse, heat stroke. People take an hour or so after lunch to rest in the shade, during the hottest part of the day, until the temperature is low enough to allow them to work comfortably.
When the European conquistadores found the native farmers napping under the trees, they thought they were lazy and stupid. The general perception that the indios had no concept of hard work and discipline further reinforced the invaders' belief in their own civilization's superiority.
Of course, to the natives, only mad dogs and Englishmen ventured out into the midday sun.
This has waned a bit, with the advent of air conditioning, although it is not unusual to see office workers in Manila or Jakarta, for example, curling up on a bench in the back room for a siesta. This is often a source of conflict between foreign bosses and underlings, who frown upon this version of the "late lunch".
System administrators like me usually unroll mats behind the racks - one of these days, someone's going to build a 19-inch rack-compatible folding cot, so every network center can have its own rack-mounted system administrator.