The difference between impedance and resistance

Al, Could you please add your take on Power Factor?
The Wiki article says that when the phase angle is 90degrees NO power is delivered.
My 'pet' idea is that reactive speaker loads are what really defines a 'bad load', not merely low impedance.

Arthur has a decent point.
I associate many speaker break-in effects to capacitors forming.
A 'virgin' cap doesn't know anything about electricity until it is in effect shown.

What got me started on this was many years ago buying a high power on-camera flash. Instructions say to fire several full power flashes when first turned on........than your good to go.

As a further aside, when i first turned on my new speakers.....some Magnepans, the image floated around quite a bit for a couple hours. Sometimes quite rapidly...flicking back and forth. Than it settled down and has been fine ever since.