Originally Posted by raymor

Half the weight of the drive is the platters spinning at 5300 or 7200 RPM. If you try to move it before it spins down there is quite a gyroscopic effect. The harder you try to turn it, the harder it pushes in a direction 90° from the direction you are trying to point it. If you react by jerking your arm to the south, the gyroscopic action converts that into the drive jerking toward the west.

That force is being transmitted through the spindle bearing, so tilting a spinning drive is a good way to ruin it. I did that once. (With 60 TB of drives for Clonebox, I've had the opportunity to see and do a lot of things with drives.)