If you don't drill, you won't win because you won't hit the target.
If you don't think about it, you won't win because you will hesitate.
Both of these are not true and have numerous folks who perform well contrary to them. In the first case, it reminds me that "only hits count." Most of the gun owners in America DO NOT DRILL or TRAIN, yet we read all the time how they win confrontations where they have fired their guns. Often they hit and often they don't, they they win. One of my favorite one shot stop stories is about an old lady in Florida who made some hells angels-type bikers mad and when a couple tried coming through her front door, she fired her tiny .25 acp just once and they fled. Two guys stopped with one shot from a puny caliber and the round stuck in the trim of the door. She won against a significant disparity of force and didn't hit either target.
Our trailer park hero was also a winner. That would be Vic Stacy who apparently put multiple shots into a gunman at some large distance (maybe 165 feet) and his story (search his name for the thread here) as told on video involved lots of thinking, hesitation, and methodical shooting and he certainly won.
These aspects are situational. Some people will fight you until their brain shuts down. Some people will run at the possibility that you have a gun. Some situations demand immediate action without thought. Other situations require careful consideration before firing.
Then of course was Mark Wilson. Seeing the gunfight from his window above the square in Tyler, TX, apparently responded without a second thought, bringing his pistol to fight a gunman armed with a rifle and ballistic and flak protection (multiple vests). Mark Wilson, a firearms instructor and gun range owner (possibly sold at the time of the event) did not think
to grab a rifle from his apartment. As such, his shots on the gunman in the square were largely ineffective except for wounding him under the vest and drawing his attention where upon he downed Mark Wilson with one shot and executed him with a second before fleeing the square and later being killed by cops. A rifle would have done Wilson well, especially if fired from his apartment overlooking the square, but he didn't think and he didn't hesitate. Mark Wilson is a hero, but a dead hero of a gun fight.