My 2p as a non-hacker outside observer is that you're very pragmatic - so you don't get caught up and immobilised by theoretical arguments - and you're motivated by a Cause, so you have the initial energy to overcome laziness. You write useful programs for the sme reason Ross volunteers at the airfield or does pretty hardcore DIY jobs round our flat: you get a kick out of knowing you're being useful.

s/volunteers/gets paid minimum wage/, but that's so close to moral equivalence...