A while ago I wrote about ensuring that you know why you're writing something in order that you keep focussed on that goal while you code. My focus at that point was on the specific project you were looking to undertake, but it may behoove us to look at the wider picture from time to time.
What motivates you?
It's important that you can answer this question, ideally without hesitation or backtracking. For each of us the answer will be different, and noone's answer is any less "right" than anyone elses. For myself, it took several years to be in a position to answer the question confidently, quickly, and consistently. That's not to say that my answer won't change in the future, but at least for now I know what motivates me and how that manifests in my day-to-day hacking.
I have had a word with Richard and he has explained his motivation to me, and so for your perusal and criticism, here's what motivates us both..
Daniel
For me, the primary motivation for writing free software is that I enjoy making
it possible for other people to achieve things. I am, as it were, an "enabler"
or "facilitator". This manifests itself in an interest in processes,
meta-programming, and tooling. I find myself writing libraries, services, and
test tooling; and I enjoy reading papers and architecture designs, thinking of
new ways to solve old problems, and novel problems to solve. (And of course,
I write articles on this here blog 
)
Richard
My motivation in general is to learn something such that it can be applied to something which in some way may be construed as to the betterment of society. Or indeed those things which may improve society directly. In the free-software world, this has manifested in the topic of reliability and also freeing people from vendor lock-in.
(* note, I kinda paraphrased what Richard said)
Homework
You didn't think I'd let you get away with no homework this week did you? Hah! I'd like you to sit down, consider your motivation in the free software world and a few ways in which that manifests into projects you work on or with. If you're feeling super-enthusiastic about it, why not post a comment on this post and share your motivation with the rest of us?