All this also really helps with meeting up with friends. I'm sure many people are familiar with playing with a friend, only to out-level them; when they want your company on lower-level content, you would go and help them purely out of friendship. However, in Guild Wars 2, you get rewarded for doing so.
I definitely found myself asking myself what I would like to do more often than I found myself wondering where the game wants me to go next. Though not a truly a sandbox in most senses of the genre, it does still have that feeling of freedom that tends to go with them.