Why did ancient Romans want to expand into the islands in the Mediterranean Sea

The growth and destiny of the Roman Empire, from a crude collection of huts in Latium on the Palatine Hill to the greatest empire the world had ever known was inextricably bound and shaped by her close proximity to the sea. Like her Greek neighbors to the East, Rome is situated on a large peninsula jutting far out into the Mediterranean. Mediterranean waters catch and hold the sun's rays during all seasons of the year, and release their warmth to the surrounding lands and littoral areas each winter. While a blizzard might rage on the other side of the Alps a few hundred miles to the North, the great body of water of which the Mediterranean consists releases its gift of the sun's stored energy slowly, causing winters to be mild and balmy except at the highest elevations.