At times, I think of managing a project as driving a car. The size of the project is the distance to cover, time is time, and effort is the fuel in the tank. The faster we do the work - the faster the fuel burns - the faster we reach the destination. Of course, provided we are traveling in the right direction.
The interesting aspect is that there is usually an optimum speed for driving. If we deviate from that we end up burning more fuel than required.
Sometimes we are forced to drive faster to reach the destination quickly. Sometimes we get into the car, stamp on the pedal and imagine that it is a rocket. Sometimes we put just enough fuel in the car for a long drive. Sometimes we do not put enough!