If a user favorites a questions, they obviously like the question or want to be able to keep track of it. They would not normally do this for a question that they have no care for (positive or negative).
Yet users will often favorite a question without voting for it.
I really do not understand why?
If you are favoriting (is there a more correct word than favoriting?) it's because it's bad, and you want to track its status, and then downvote it.
If you are favoriting it because it's great, then up-vote it. Even if you feel it only pertains to you, that's still worth a vote indicating that it is of importance to someone other than the OP.
I have read in other discussions that it is much harder to get someone to vote on a question rather than an answer. Well, what if you cannot favorite a question until you have voted it (up or down)?