I have never once finished a GTA game. It's just impossible for me. I'm usually side tracked or I get bored and just ride around town killing people. This was the issue for all GTA games with me, including the original GTA games.
I finished GTA 1,2,3 and Vice City. I was playing GTA San Andreas but later I came to know that it has been given Adult rating, so I stopped it midway....
I didn't knew about Grand Theft Auto 3. I have played Grand theft Auto Vice City first then after finishing it 3 or 2 times (not 100 percent) I stopped playing it and then I saw Grand Theft Auto 3 on the GameFaqs.com, bought it and started playing it but when I was about to finish the game (again not 100%) It gets boring and I stopped playing it.
Now finally Its Grand Theft Auto San Andreas so yes, I have finished it 3 times (not 100 percent) even when it got Adult Only rating . It was very fun and addictive game and Is one of my best games ever.
Only ever finished Vice City (89% or something), San Andreas was 29% after weeks of playing. It just got to much trying to keep the chick happy whilst keeping all my skills at the top and all the stats at the top. Ontop of all this living life. The game is trying to take us away from reality and make us live in the game.