It might be Banks utopia but the Culture seems more like Calhoun's rat utopia experiment to me or Douglas Adams' "long dark teatime of the soul". There's nothing to strive for, there's nothing one could do that hasn't been done better by a quadrillion other beings and utterly eclipsed by the Minds. It's so spiritually sterile that a ships crew collectively gives themselves a cold (normally prevented by their medical tech) just for the sake of the experience and breaking the monotony of their existence.