Most of us readily have a list of goals that come to mind, but it's likely that they are subgoals and we are unaware of why exactly we do them. So, you keep on asking "What will this goal do for me?" instead of "What will do this goal for me?", creating downwind nodes your graph until you presumably hit your preferences.
That's interestingly dual to what I have in mind: the core notion is that it shows you one thing to do (as opposed to a list, to avoid excess choice or dismay). And if you want to not-do-that, you have choices such as:
That last option is what sounds similar to what you're doing, but it supposes you've already entered dependency chains all the way up to preferences. Which might be another sort of one-thing the app presents you with: “Why do you want to do this thing you entered previously?” (Which information isn't mandatory, because it should still permit quick entry of simple reminders.)
Obviously this has a whole lot of scope, the extreme case becoming a complete “outboard brain” planning system, but I'm hoping that (if I ever get around to programming it) it'll be useful even in a rudimentary form.
My notion is that managing dependencies allows avoiding the problem of having a long to-do list which you have to actually look at and consciously reject items for not being something for this exact moment, thus leading to the habit of rejecting all of the items; instead, nearly all of the “list” will be filtered out by some dependency (which ends up being another task, a topic of interest (e.g. a hobby that you only do sometimes), a time, a location, etc.) and you need not ever think about it.
That's also the reason why the user interface I imagine defaults to presenting you with exactly one item at a time: each interaction you have with it gives it more data, but there is never a long list or form inviting you to deal with many items, or many fields-to-fill-out about a single item.
But, this is all vaporware.
I've found most graphing software too clunky, or having too much mental friction, for my purpose of creating graphically represented plans, to convert written diagrams into digital form, or to do preference inference based on the structure of my goals (amongst other things).
So far the only tool that I've seen that reduces this friction is GraphViz [1], since I think I can literally just list down connection after connection in markup, with no care for structure or reasonableness, and then prune connections after I see how the entire thing looks. Point and click is for suckers.
However, I also like the approach of Freemind that quickly outputs a visual map that is easily traversable; but it doesn't do much for me when the causality is more involved.
Are there any alternatives that anyone is aware of?
[1] If you are not familiar with GraphViz, see this amusing introduction that maps the social network in R. Kelly's hit hip hopera, "Trapped in the Closet".