I enjoy teaching and mentoring other developers. I did not have a mentor when I first started writing software, so I learned many lessons the hard way. Helping others avoid those pitfalls is extremely satisfying.
I'm a big fan of open-source software. I do not believe proprietary software violates human rights, but I know too well the frustration of being dependent on a vendor for critical changes. I default to open-source programs and use proprietary ones only if there is a compelling reason.
I would love to have an open-source, real-time, auto-scaling audio DSP engine for general-purpose hardware - something like an open-source Kyma for arbitrary hardware. Discovering this already exists would be spectacular, but since I have not yet found it, I daydream about building it.