If you are trying to loosen a stubborn screw from a piece of wood with a screwdriver and fail, should you find a screwdriver for which the handle is longer or fatter?

Answer: longer screwdriver

Explanation:

A longer screwdriver will work because it would increase the torque in loosing the screw

Knowing that torque I the product of weight and distance this mean that the more the distance the more the torque that is required to loosen the stew.

A fatter handle. This allows you to provide more torque to the screw, which should eventually loosen it.