I have been thinking of this for a while now so i decided to put this idea out there. I know i am missing many quests but i dont know where to look and i think it would be easier if in the quest log it told you whjat quests you missing in which world and where and from what person so you can go back and finish them. If anyone agrees or has a better idea go on and post away! :D
The quest log only shows you the quests you've accepted and haven't completed yet.
It's your job to find quests and it's very easy to do. As you enter an area, look at your map. All the interactive NPCs will be shown. Go to each one and get their quests, even if you don't intend to do it right away.
It's much easier later on to know what you have to finish then it is to look for quests you haven't received.