Right now if you land on a quest sight and don't want to do it, it will go away completely.  Would rather just have the quest not start but be able to come back to it later.  In many cases this may not matter but for things like escort quests you may need a strong group if you are in dangerous territory.

Also if you arrive at a quest destination and don't do it you fail the quest or it goes away.  In my case I wandered on a quest destination where I needed to fight but didn't have a group strong enough for that.  Just because I didn't fight shouldn't mean the quest has failed.

One other thing this game really needs is some sort of quest log.  Once you get a few it can be hard to remember what they are or what you were supposed to do.  This will become more of an issue later with the more complicated quests I think you will have.