[Kimble]

1) I played all of the GTA's but the only one i keep getting back to is GTA SA and it's because of SA-MP ofc. Why?
a) A wide variety of servers (even though RP is the most popular one you can find plenty of others).
b) I can try them out really fast (no annoying downloads like on Garry's Mod) (waiting for an hour just to be disappointed).
c) The community seems closer. People play on the same server for a while and become friends, unlike GTA Online where they play on a different server everyday (same game, different server, different people). It seems that community triumphs over nice graphics.

2) I was a player once and while i was just a player a lot of times i thought "wow it would be cool if they addded X" but for whatever reason that didn't happen so finally after i learned how to script i added those things and opened up my server. Ran it for a while then gave it away when i didn't have time anymore. Time was probably the reason why they never added the things that i wanted when i was a player.

3) It was a sandbox game to begin with -- the multiplayer aspect just opened up a thousand more possibilities for it.

Off Topic: Nice of you to promote SA-MP.