[TeMPOraL]

Complexity != abstraction != leverage.

Today's software suffers from too many layers of complexity that are each pretty dumb and serve mostly bookkeeping. The result looks like an overinflated bureaucracy. In the example above, using a more efficient data structure for text representation will add at most one layer of abstraction (but there's a good chance you'd create that layer to hide the array anyway), but offer significant benefits in terms of performance, at a cost of little and well-isolated complexity.

This is the best kind of abstraction: complex, deep behavior hidden behind simple interface.