Not all service is at the third level of happiness. If you only engage in service on your own terms, instead of responding to the real evident needs of those around you (and if you are actively seeking to discover the real needs of those around you), then your service is only being engaged in for the sake of your own ego gratification, rather than for the real good of the other, a requirement for pursuing happiness on the third level.
George Bailey in It's a Wonderful Life is the archetypal pursuer of happiness on the third level. Bedford Falls didn't appear to him to have much to offer in the way of making his own personal dreams come true. But (with the encouragement of his wise father), he chooses to respond to the real needs of those around him rather than pursue the ego gratification that his dreams of travel and success would give him.