Bread hydration (water weight / flour weight × 100) determines crumb structure and handling difficulty. A 65% hydration dough behaves like clay — stiff, easy to shape. An 80% hydration dough is slack and requires technique.
Higher hydration produces a more open, irregular crumb with large holes (ciabatta, sourdough). Lower hydration produces a tighter, more uniform crumb (sandwich bread). Neither is superior — they suit different purposes.
The difficulty: high-hydration doughs are hard to shape because they stick to everything. Cold retarding (overnight in the fridge) stiffens the dough and makes shaping possible. The tradeoff is time for workability.
Related: salt-ratios, fermentation-as-preservation