Who are your pirates?

What I mean is where do they come from? Are they born into the pirate life or is it something they come to out of desperate need?

Are they rogueish freedom fighters or canny merchants? Do they have a family a home and a quiet life to return to or do they live and die on the run from the powers that be?

What booty and loot can they lay claim to? What unwary travellers do they lay waste to? What fate awaits a captured or defeated pirate?