Consider Phlebas (Culture, #1)

by Iain M. Banks

The only desire the Culture could not satisfy from within itself was one common to both the descendants of its original human stock and the machines they had (at however great a remove) brought into being: the urge not to feel useless. The Culture’s sole justification for the relatively unworried, hedonistic life its population enjoyed was its good works; the secular evangelism of the Contact Section, not simply finding, cataloguing, investigating and analyzing other, less advanced civilizations but—where the circumstances appeared to Contact to justify so doing—actually interfering (overtly or covertly) in the historical processes of those other cultures.