Came across an interesting entry in Fast Company Magazine's blog: Feedback and Forth.
Bottomline: people or teams who experience at least 2.9 times more positive experiences than negative experiences over any span of time is more likely to be a "flourishing" individual, partnership, or team.
The original full report is also publicly available.
Interestingly, too much positivity is also bad. At a positive-to-negative (P/N) ratio of more than 11.6, flourishing deteriorates.