I was aware of the existence of GTA 1 and 2 only because I saw reviews in magazines and the cases on the shelves in shops. Didn't interest me in the slightest. Seriously the first time I saw a GTA 1 screenshot I thought maybe it was Rally X 2000 or something.
I remember when GTA 3 released and took over the world over night. I thought the 3D open world tech was amazing, but the game itself still didn't interest me. My best friend pretty much literally forced me to borrow his copy, promising that if I just tried it I'd love it. I played it for about three or four hours. I didn't love it.
Just kept ignoring GTA over years. Had a bit of a wake up call when San Andreas swept all of the 2004 GotY polls. I knew it was a popular franchise but didn't realize it was bigger than Halo/Half Life/MGS/Metroid Prime combined. Still didn't give a shit, chalked it up to the same human condition that causes hundreds of millions of people to buy Britney Spears CDs etc.
When Read Dead Redemption released, I caught a lot of people saying "Even you hate GTA, you should try RDR. It's one of the best games ever made and it's really nothing like GTA at all." I decided to try it, and sure enough I loved it. A little later, I caught other people basically saying, "Wtf is this crap about RDR being nothing like GTA? IT'S EXACTLY LIKE GTA. It's basically GTA4 set in the old west." It is? Well then shit, I need to play GTA4! I think that was actually the first digital console game I ever bought, GTA4 on 360. I played it up to the point where you get the second safe house and stopped there for some reason, even though from what I recall I was enjoying it. Months later, LA Noire released and I played that and loved it. Somehow that was what triggered me to go back and start over with GTA3, finish it, play through Vice City, play through San Andreas, and then finally go back and finish GTA 4. After that, I was pretty much as big of a GTA fan as the next dude.
Anyway, my first GTA was RDR1.