Gage said:
Playing pool is about the most unnatural thing a person can do, so practice is necessary to improve our abilities beyond what they naturally are.
I never said that practice is unessary. (Perhaps it came accross that way) so I will elaborate.
Practice IS necessary to get the proper Stance / Grip / Alignment / Pattern Play / Shot Selection Skills / Creativeness / Experience.
The key point is that none of these are "moving" parts. The actual motion back and through must be "natural"..meaning no thought or forced motion whatsoever....Example

ulling the cue back a certain distance, follow through a certain distance, cupping your wrist in or out "during the stroke".....as soon as you "force" any of those movements during practice, it is now a "unatural' stroke....You may be able to repeat this 1000 times during practice....but when the money is on the line and your "under pressure" you will revert to what comes "natural"...You may be able to "normally" overcome the tendancy of your "natural" movement, but it will cost you at those "key" moements in matches.
So...how do you fix bad strokes....by changing the non-moving parts or "set up".....Happens to be the same way you fix a golf swing...(which by the way is the most unatural movement for a human body)... The pool stroke is very natural if you stop to think about it...Really it is not much more than a underhand throwing motion...
For some the proper set up still produces a "ugly" but very effective and accurate stroke....for the lucky ones it produces a socially accepted "good looking" stroke that is also "effective"
That is why you won't see Nick Varner attempt to remove his "hitch" in the stroke.........or Scott Frost attempt to remove the roller coster movements....why would they need to...thier natual movements produce very very solid contact.