"If you set your torque wrench to lets say 150 Nm & proceed to tighten a head bolt, you will see a significant difference in the final resting position of the bolt, depending on your technique. For example, if you perform the final tightening action, in one fluid movement, without pausing, you will find that the resting position of the bolt will be further (read tighter) than if you were to pause momentarily before the final 150 Nm torque wrench "click off" is heard. The momentary pause will often cause the torque wrench to "click off" prematurely before a further movement has taken place, giving an misleading indication that the bolt is tight enough"

Dave, A nice explanation of static and dynamic friction the force required to start and keep moving an object demonstrated (a few moons ago!) in a physics lesson attaching a newton gauge to a block and pulling along a flat surface the gauge rises then when it starts moving the force required to keep it moving reduces, and then if lube added...

Rob