I have had many experiences in GTA:O, but I'll share a couple of them now that happened around the same time. Warning, this is going to be a large post.
The first incident occurred pretty early on in my GTA:O career. I had just gotten my first text from Simeon about delivering vehicles so naturally I had no idea of what usually happens around these things...
Anyways, I believe my first vehicle was the Landstalker (not positive, gotta try and remember later), so I take it to LSC after ditching the authorities, fix and respray it, then carefully drive the long distance to Simeon's garage, not paying a lick of attention to two blips around the area as I'm figuring they were out in boats or something. I drive into the garage area and me, being my initial naïve self, see the two just standing around the garage. I thought, Oh well, those guys are probably just chillin' or took a break.
I drive up to the garage door and seconds later I am nothing but a mass of blood and gore as one of them empties a micro-SMG clip into my head before I can react. At this point I think WTF? and respawn nearby, where those two players are busy shooting it out with each other (neither of them taking the bloody car!). I get angry and pull out my shotgun and when one of them finally wastes the other blow the survivor into pieces with the trusty rat-food maker. I get in the still-vacant car and drive it in and collect my money, end up outside and Bang!! am instant luggage again as one of the same dudes (the one with the micro-SMG left) empties his shotgun into me. I respawn again, am doubly angry and in my rage pull out my nightstick and charge the guy. For some reason he pulls out his pistol and starts banging away. I am pleasantly surprised when all but one or two of his bullets miss me and before he can pull out another weapon or reload I beat the h*ll out of him and leave him in a bloody mess on the concrete. In a flash I jack a car and hightail it out of there, still wondering despite my anger what the h*ll happened.
My second incident happened four or five hours after that, when I am rapidly losing my naivety and becoming more GTA:O-wise. I happen to be driving around the Sandy Shores area when I hear over my headset that there's a group of guys that are going to be stealing some Lazers but are having a devil of a time organizing their merry band. At this point I think The more the merrier and take my Vapid Dominator cross-country, practically destroying the bloody thing, and eventually come up to their area (not saying a word the whole time in spite of my microphone).
They are taking off in Sandkings towards Fort Zancudo, somewhat more organized. I instantly abandon my severely damaged Dominator in favor of a jacked Sandking and speed off after them. I catch up to them as they have stopped along the way, due to one of their gang jumping out of the lead truck randomly, and they notice me back there. At this point they ask themselves over their microphones Who the f*ck is this guy? I turn my microphone off to keep my chuckles from being heard. After more bickering and talking, the jumper gets back in and they continue towards the fort, me bringing up the rear. Two of them keep talking about me as I am following them, but the "leader" decides that Well, he f*cking ain't shooting or anything, so whatever.
So here I am, mic turned off, following a bunch of dudes who keep talking into their mics. They head up the mountain by the fort, me right on their tails. After more trial and error and damaging Sandkings, we all get into position and make the jump into Fort Zancudo, me right behind them, low-level and all. They speed around the fort and get their Lazers, but me and a few others (including the "leader", though I was not aware of it at the time) are left on the ground. They know where they are going and escape the fort, but I am as lost as could be and am getting pulverized by the military, though not killed (yet). Finally I crash into the walls of the fort and find a box next to the wall. I abandon my stolen Sandking, leave the fort, and take off on foot (and am being watched by the others, though I am unaware of it at the time and am not paying attention to the voice chatter in my headset).
At this point I keep thinking holy sh*t! over and over as I run on my low stamina character. In a blind panic I run into the lake and start swimming to the other side. For some reason I am not killed by this idiotic action either as I frantically swim to the other side, despite choppers being above me and my low stamina. I make it to the other side, run up to the nearby road and BAM! am hit by a speeding cop car.
I respawn and notice that the "leader" of the group has sent me a friend request. At this point I find out that they had been watching my mad "escape" from the fort the whole time. I turn my mic and talk to them for a while, then join them on a few missions.
All of this happened in a relatively short time, and it was after the second major incident I looked at my character and said into the mic...
Welcome to GTA Online.