If you did this in Georgia, what you did was likely highly illegal. It's a very serious crime. You may not brandish your weapon in any manner unless you can prove that your life is in danger, or you are stopping a felony in progress. I believe brandishing a weapon is a felony in GA.
Thank you for your on the spot legal analysis. That said, once again, you're wrong. For one, the incident happened down in Tampa, FL and it happened around 10-12 years ago. It was a road rage thing where some guy driving a commercial delivery truck literally flipped his shit in the middle of rush hour on Dale Mabry Highway (6 lane road at that point). Traffic stopped, he got out of his truck behind my car, came around to my father's side (front passenger) of my car (I have no idea why) and is screaming and demanding to "get out of the car" and that he's "going to kill you". Neither of us says a word in reply but the guy gets madder and starts to threaten to punch the window in. He's still there (because traffic is still stopped) and he's getting more irate by the moment to the point where he balls up a fist and starts to (I don't know that I can describe this correctly) starts to sway back and forth like he's getting ready to slug the window.
At the time I owned a 9mm Browning and kept it in a zip case in the middle console of my car. I open the console, withdraw the pistol from the case and simply set it in my lap with my hand on it, the whole time staring at the guy. Out of sight from literally any other person other than us and the assclown outside. He goes on for perhaps another 5 seconds and all of a sudden, apparently sees the gun because his trap shut with what I'd like to recall was an audible "clop" and goes back to his truck. End of incident. According to the law at the time (may have changed since, I don't know) I was entirely in my right to do what I did and had he slugged the window and broken the glass that, coupled with his death threats, would have been ample enough reason. Thankfully, the presence of the gun meant he knew he wasn't going to be a big tough guy and slug an old man through a car window without consequences.
As for "highly" illegal, you, unsurprisingly, have no clue what you're talking about. The only thing remotely similar that IS illegal is if I point it at someone "without legal justification" and even if I do that, it's not "highly illegal" it's a frickin' misdemeanor...you know...like that other "highly illegal" jaywalking crime. Just so we're clear: the permit I possess is a carry permit. Not a concealed carry permit. If I like (and don't mind the hassle it will generate from law enforcement) I can carry the damn thing down the street in my hand and it's 100% legal (although not advisable).
Seriously man, just because the thought of a gun causes you to wet your pants doesn't mean every Hollywood scenario you've seen on CSI or whatnot is true.