maybe people who are happier don't spend as much time thinking about their own condition as unhappy people, and are thus more free to think about others' condit

maybe people who are happier don't spend as much time thinking about their own condition as unhappy people, and are thus more free to think about others' conditions. or maybe people who are happier in general take more pleasure in giving to others than people who are unhappy in general, and thus they continue to do so. there are numerous causation possibilities. (that said, at the end of the day, being happy is a win for everyone.)