I have to say that I find a cause devoid of adventure to be more depressing. Human beings tend to have a built-in ability to adapt, so if they have no map for their adventure, they'll make one. That's pretty much where Cartography came from. When human beings are presented with a problem, they invent ways to solve it. (Some of them, though certainly not all, even work more or less the way they're supposed to.)

I find, however, that I must have a reason for the causes to I they devote my time and energy. It seems to me that the adventure inherent in any cause is the playing out of the consequences of the cause, curiosity being the catalyst for the adventure, and the adventure itself being the path the course of events take, the journey to the ultimate conclusion itself. If there is no adventure, it would be because, simply put, nothing's happening, and I, for one, probably would go insane within 20 seconds in a world where literally nothing happens. I think that human kind, having witnessed, collectively, as a species, the progression of time and the development of society and of all the relationships between humans and themselves, humans and animals, humans and plants, etc., and having grown so accustomed to it that it almost seems a longing for progression has been written into our souls themselves, simply could not stand a world in which there is no progression.

In other words, no one needs to die at the end of their journey for lack of a map. They can make a new map. But unless they continue their journey always, until it is done, there's not really much need for the map at all. I think the adventure in a cause is far more vital than the cause of an adventure. It seems to me that it doesn't really matter what causes an adventure as long as the adventure does indeed happen. :p

By the way, I'd just like to add that I really liked this question. Thanks for asking it.