Firing a handgun
The mechanics of firing a handgun are easily understood. You hold it, put the sights on the target and squeeze the trigger. It goes bang and if your mechanics are good, a hole appears in your target in the spot you were aiming at.
But, if you're a new shooter, the next shot is rarely on target. The mechanics are good, but you flinch, blink your eyes or experience some other involuntary movement in anticipation of the gun going bang.
As you become a better shot, not only does the mechanical aspect of your skill become more refined, your mental control becomes better. You "get used" to the noise and recoil.
You graduate from shooting holes in a stationary target to tactical handgun training. You work on firing a handgun in a defensive situation instead of poking holes in paper targets.
As we've covered in other articles, personal safety starts with avoiding being caught in a bad situation. As a law abiding member of society you've probably been "fat, dumb & happy". Just getting thru each day without much regard for what is going on around you.
Once you decide to become more concerned with personal safety, you start paying attention to your surroundings. You notice what's going on around you, how people are interacting with each other and how they react to your presence. Your clothing, facial expression and posture all combine to give people an impression of you.
You want to be able to provide the proper impression as you go about your daily activities. You don't want to be the baddest guy on the block because that invites challengers (there is a time and a place for this posture). You don't want to seem oblivious because that invites predators. You want to appear to be unremarkable most of the time. Aware of your surroundings but not scanning them as if your head is on a swivel. Think of how an undercover police officer my "blend in" while on a stake out. That is your general goal.
Use of force
You must be mentally prepared to deal appropriately with a threat to your safety. Just because you have a gun (think hammer) doesn't mean every threat is a nail.
You must be able to decide if there is a need to make use of your handgun and what that use is. Do you just reveal it, draw it or are you going to have to actually fire it. Are you mentally prepared to fire it if the need arises. Just remember, any use of your hand gun (you don't even have to touch it to "use" it) has the potential to send you to jail.
Once the threat is over, you'll have to deal with legal (and potential civil) consequences. On top of that, you will have to deal with the emotional consequences. If you took a life, society will always see you as a killer. It may have been justified, but as a civilian taking a life is morally taboo. You may find that some people can't get past it. You may lose your job because your coworkers are afraid to be around you. You may lose your spouse because you suddenly appear to be a different person. They can't come to terms with the type of person they thought you were and the type of person that they now see you as.
To be clear, it's not your fault how others now perceive you, but you will pay the price for that perception.