I've played since it first was released. It's an amazingly sick game and I'm no hardcore rpg player or anything. The only thing that will ruin it is getting caught up in playing with hacked items or playing simply to better your character (IE killing the same boss over and over). Try to stick to playing by the story line and get immersed in the different acts (There's 4-5 acts). And don't get into being "Rushed" which is rush leveling in which a very high level friend helps you through the game and gets you experience really quick. The fun part in the game, as said above, is the character development so stick with it and take your time
Man I wish I could be playing that game for the first time (See my "Will there be a Diablo 3?" thread
)
-T