upbeat

(noun) a contented state of being happy and healthy and prosperous. Synonyms: wellbeing, well-being, welfare, eudaemonia, eudaimonia. Example: "The town was finally on the upbeat after our recent troubles."

(noun) an unaccented beat (especially the last beat of a measure). Synonyms: offbeat.

(adj) pleasantly (even unrealistically) optimistic. Synonyms: cheerful, pollyannaish.