Apparently it takes $8 million.

Researchers at Harvard University found that millionaires who were worth more than $8 million rated themselves as happier than those who were worth less than $8 million.

It’s unclear why this is the tipping point. It could be that’s the magic number of $8 million puts high net worth people ahead of their peers, boosting their perceptions of self-worth. Or, maybe $8 million is the amount where millionaires feel their money is safe enough to spend freely on things like charity and big gifts.

Either way, it's good to know just how much is needed to turn that frown upside-down.