I honestly think people focus too much on pain relief/solving problems vs. making people happy. Most ideas can be described in either paradigm, and there's really no reason to argue about it - just make something people want. Maybe they want it because it makes them happy, or maybe it makes them way less sad.

Take bookmarking. Del.icio.us made people really happy because they could keep track of all the sites they liked. It also made people way less sad because they didn't lose track of sites they liked. Either way, people used it.